few problems that have been cropping up for me lately:

1) every time i open a youtube video a window called data execution prevention pops up, close it, option to report error window pops up, then whether i report or not my taskbar disappears for a few seconds then comes back. video plays fine despite all this.

2) while playing a videogame, left4dead primarily, game will randomly freeze and lock up my computer, only way out is to reboot. some days im fine, other days ill crash 1 minute into a game over and over. seems to be completely random so i dunno.

3) probably the most serious error, every now and then at complete random a window will pop up called Microsoft Visual C++ Runtime Library, saying C:\WINDOWS\Explorer.EXE isnt working. when i close that message no matter what im doing ill be forced to desktop, all icons and taskbar are gone but my backround image remains. interestingly when im on vent i can still talk and hear others for a bit despite having no visuals, but again the only way out is to reboot.

4) general slowing down of pc, internet takes longer, programs take longer ect. unsure of the cause as i dont think my computer is infected with anything, but who knows. any help is greatly appreciated.

this all seemed to worsen when i did a disk defragmentation a few months back, i hadnt previously defragmented and my pc is about 3? (not sure exactly) years old now. had the usual occasional problems and slowing down, but after defragmenting things got a lot worse.

here is my log:

Logfile of HijackThis v1.99.1
Scan saved at 6:23:36 PM, on 4/23/2009
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16827)

Running processes:
C:\WINDOWS\System32\smss.exe
C:\WINDOWS\system32\winlogon.exe
C:\WINDOWS\system32\services.exe
C:\WINDOWS\system32\lsass.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\system32\PnkBstrA.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\ctfmon.exe
C:\Documents and Settings\Brenden\Desktop\hijackthis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = Google
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = MSN.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = Live Search
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = Live Search
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = MSN.com
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Int ernet Settings,ProxyOverride = *.local
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - %windir%\Network Diagnostic\xpnetdiag.exe (file missing)
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - %windir%\Network Diagnostic\xpnetdiag.exe (file missing)
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O10 - Unknown file in Winsock LSP: c:\program files\bonjour\mdnsnsp.dll
O11 - Options group: [INTERNATIONAL] International*
O15 - Trusted Zone: MessageFromMe: Something Special to Say ? Say it with a Media Message !
O16 - DPF: {02BF25D5-8C17-4B23-BC80-D3488ABDDC6B} (QuickTime Object) - http://appldnld.apple.com.edgesuite....x/qtplugin.cab
O16 - DPF: {4871A87A-BFDD-4106-8153-FFDE2BAC2967} (DLM Control) - http://dlm.tools.akamai.com/dlmanage...ex-2.2.4.1.cab
O16 - DPF: {67A5F8DC-1A4B-4D66-9F24-A704AD929EEE} (System Requirements Lab) - http://www.systemrequirementslab.com/sysreqlab2.cab
O16 - DPF: {67DABFBF-D0AB-41FA-9C46-CC0F21721616} (DivXBrowserPlugin Object) - http://download.divx.com/player/DivXBrowserPlugin.cab
O18 - Protocol: livecall - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\MSNMES~1\MSGRAP~1.DLL
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\MSNMES~1\MSGRAP~1.DLL
O23 - Service: FLEXnet Licensing Service - Acresso Software Inc. - C:\Program Files\Common Files\Macrovision Shared\FLEXnet Publisher\FNPLicensingService.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Common Files\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: iPod Service - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: PnkBstrA - Unknown owner - C:\WINDOWS\system32\PnkBstrA.exe

Welcome,

To clean your temp folder, recycle bin, etc..please download this free tool:

CCleaner

Don't install any Toolbars, or other programs, should it ask you!Just uncheck the option of installing the Yahoo toolbar.
It will put a shortcut on your Desktop.

Uncheck cookies

Before first use:
Select Options then Advanced.
UNCHECK "Only delete files in Windows Temp folder older than 48 hours"

Click on CCleaner to start it. Then click "Run Cleaner", just use the windows tab up front by default.


Then Reboot (Exit)


Please download and install the latest version of HijackThis v2.0.2:Delete the old version you have

CLICK HERE to download the HijackThis Installer:TrendSecure | Download TrendMicro HijackThis

1. Save HJTInstall.exe to your desktop.
2. Double-click on HJTInstall.exe to run the program.
3. By default it will install to C:\Program Files\Trend Micro\HijackThis.
4. Accept the license agreement by clicking the "I Accept" button.
5. Click on the "Do a system scan and save a log file" button. It will scan and then ask you to save the log.
6. Click "Save log" to save the log file and then the log will open in Notepad.
7. Click on "Edit -> Select All" then click on "Edit -> Copy" to copy the entire contents of the log.
8. Come back here to this thread and paste the log in your next reply.
9. Do NOT have HijackThis fix anything yet! Most of what it finds will be harmless or even required. Post the new hijackthis log after running malwarebytes please.


* Please download Malwarebytes' Anti-Malware from HERE or HERE

Double Click mbam-setup.exe to install the application.

* Make sure a checkmark is placed next to Update Malwarebytes' Anti-Malware and zLaunch Malwarebytes Anti-Malware, then click Finish.
* If an update is found, it will download and install the latest version.
* Once the program has loaded, select "Perform Full Scan", then click Scan.
* The scan may take some time to finish,so please be patient.
* When the scan is complete, click OK, then Show Results to view the results.
* Make sure that everything is checked, and click Remove Selected.
* When disinfection is completed, a log will open in Notepad and you may be prompted to Restart.(See Extra Note)
* The log is automatically saved by MBAM and can be viewed by clicking the Logs tab in MBAM.
* Copy&Paste the entire report in your next reply along with a fresh HijackThis log.


Extra Note:
If MBAM encounters a file that is difficult to remove,you will be presented with 1 of 2 prompts,click OK to either and let MBAM proceed with the disinfection process,if asked to restart the computer,please do so immediatly.

ok ran the programs you listed

malware log:

Malwarebytes' Anti-Malware 1.36
Database version: 2036
Windows 5.1.2600 Service Pack 2

4/24/2009 3:54:12 PM
mbam-log-2009-04-24 (15-54-12).txt

Scan type: Full Scan (C:\|)
Objects scanned: 157777
Time elapsed: 27 minute(s), 41 second(s)

Memory Processes Infected: 0
Memory Modules Infected: 1
Registry Keys Infected: 1
Registry Values Infected: 1
Registry Data Items Infected: 0
Folders Infected: 0
Files Infected: 1

Memory Processes Infected:
(No malicious items detected)

Memory Modules Infected:
C:\WINDOWS\system32\midadDrv.dll (Spyware.Agent) -> Delete on reboot.

Registry Keys Infected:
HKEY_CLASSES_ROOT\CLSID\{6ecb0be8-933c-91d2-c901-9a81e135d25a} (Spyware.Agent) -> Quarantined and deleted successfully.

Registry Values Infected:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Curr entVersion\Explorer\ShellExecuteHooks\{6ecb0be8-933c-91d2-c901-9a81e135d25a} (Spyware.Agent) -> Quarantined and deleted successfully.

Registry Data Items Infected:
(No malicious items detected)

Folders Infected:
(No malicious items detected)

Files Infected:
C:\WINDOWS\system32\midadDrv.dll (Spyware.Agent) -> Delete on reboot.

================================================== ==
HJT log:

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 4:02:27 PM, on 4/24/2009
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16827)
Boot mode: Normal

Running processes:
C:\WINDOWS\System32\smss.exe
C:\WINDOWS\system32\winlogon.exe
C:\WINDOWS\system32\services.exe
C:\WINDOWS\system32\lsass.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\system32\PnkBstrA.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\Trend Micro\HijackThis\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = Google
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = MSN.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = Live Search
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = Live Search
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = MSN.com
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Int ernet Settings,ProxyOverride = *.local
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O15 - Trusted Zone: MessageFromMe: Something Special to Say ? Say it with a Media Message !
O16 - DPF: {02BF25D5-8C17-4B23-BC80-D3488ABDDC6B} (QuickTime Object) - http://appldnld.apple.com.edgesuite....x/qtplugin.cab
O16 - DPF: {4871A87A-BFDD-4106-8153-FFDE2BAC2967} (DLM Control) - http://dlm.tools.akamai.com/dlmanage...ex-2.2.4.1.cab
O16 - DPF: {67A5F8DC-1A4B-4D66-9F24-A704AD929EEE} (System Requirements Lab) - http://www.systemrequirementslab.com/sysreqlab2.cab
O16 - DPF: {67DABFBF-D0AB-41FA-9C46-CC0F21721616} (DivXBrowserPlugin Object) - http://download.divx.com/player/DivXBrowserPlugin.cab
O23 - Service: FLEXnet Licensing Service - Acresso Software Inc. - C:\Program Files\Common Files\Macrovision Shared\FLEXnet Publisher\FNPLicensingService.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Common Files\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: iPod Service - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: PnkBstrA - Unknown owner - C:\WINDOWS\system32\PnkBstrA.exe

--
End of file - 3549 bytes

What is going on now?

Hijackthis log is clean.

malwarebytes found some infection and cleared those.

ah thats good to hear HJT didnt find anything. everything seems to be splendid at the moment, ill report back if that changes at all. thank you very much for the help, the random crashes were driving me nuts. thanks again!