When I enter Windows XP SP2, it starts up normal, but soon after startup, the System (Not System Idle Process) seems to use up 99 CPU usage.

Here's a list of the all the programs in process, unforunately, I cannot access Windows XP normally, so I'm using Safe Mode with Networking...

Logfile of HijackThis v1.99.1
Scan saved at 4:43:50 PM, on 4/30/2005
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP2 (6.00.2900.2180)

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\Explorer.EXE
C:\Program Files\Mozilla Firefox\firefox.exe
C:\WINDOWS\system32\taskmgr.exe
C:\WINDOWS\system32\rundll32.exe
C:\DOCUMENTS AND SETTINGS\CHRIS\DESKTOP\hijackthis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = http://us.rd.yahoo.com/customize/yco...search/ie.html
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://us.rd.yahoo.com/customize/yco.../www.yahoo.com
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://webmail.adelphia.net/webedge
O3 - Toolbar: Yahoo! Companion - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn0\ycomp5_5_7_0. dll
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKLM\..\Run: [Fellowes Proxy] C:\WINDOWS\System32\r3proxy.exe
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [ViewMgr] C:\Program Files\Viewpoint\Viewpoint Manager\ViewMgr.exe
O4 - HKLM\..\Run: [NeroFilterCheck] C:\WINDOWS\system32\NeroCheck.exe
O4 - HKLM\..\Run: [Zone Labs Client] "C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe"
O4 - HKLM\..\Run: [SunJavaUpdateSched] C:\Program Files\Java\jre1.5.0_02\bin\jusched.exe
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKLM\..\Run: [pccguide.exe] "C:\Program Files\Trend Micro\Internet Security 2005\pccguide.exe"
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\WINDOWS\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKCU\..\Run: [MSMSGS] "C:\Program Files\Messenger\msmsgs.exe" /background
O4 - HKCU\..\Run: [AIM] C:\Program Files\AIM\aim.exe -cnetwait.odl
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_02\bin\npjpi150_02.dll
O9 - Extra 'Tools' menuitem: Sun Java Console - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_02\bin\npjpi150_02.dll
O9 - Extra button: AIM - {AC9E2541-2814-11d5-BC6D-00B0D0A1DE45} - C:\Program Files\AIM\aim.exe
O9 - Extra button: (no name) - {CD67F990-D8E9-11d2-98FE-00C0F0318AFE} - (no file)
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
O16 - DPF: {01111F00-3E00-11D2-8470-0060089874ED} - http://supportsoft.adelphia.net/sdcc...d/tgctlins.cab
O16 - DPF: {74D05D43-3236-11D4-BDCD-00C04F9A3B61} (HouseCall Control) - http://a840.g.akamai.net/7/840/537/2...ll/xscan53.cab
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: Trend Micro Central Control Component (PcCtlCom) - Trend Micro Incorporated. - C:\PROGRA~1\TRENDM~1\INTERN~2\PcCtlCom.exe
O23 - Service: Trend Micro Real-time Service (Tmntsrv) - Trend Micro Incorporated. - C:\PROGRA~1\TRENDM~1\INTERN~2\Tmntsrv.exe
O23 - Service: Trend Micro Personal Firewall (TmPfw) - Trend Micro Inc. - C:\PROGRA~1\TRENDM~1\INTERN~2\TmPfw.exe
O23 - Service: Trend Micro Proxy Service (tmproxy) - Trend Micro Inc. - C:\PROGRA~1\TRENDM~1\INTERN~2\tmproxy.exe
O23 - Service: TrueVector Internet Monitor (vsmon) - Zone Labs LLC - C:\WINDOWS\system32\ZoneLabs\vsmon.exe

So you cannot boot normally into XP? What happens? Even it it's slow that would be the place to try to locate the process.

If this just started to happen you can try a System Restore or Last Good Config from Safe options & or:

Look in your Event viewer: rt. click My Computer then click Manage then Event Viewer.
Or: Administrative Tools/Event Viewer or Start/Run/ eventvwr
Open the system as well as the application tabs & look for X errors. Click error line for details.
Post back the source & event id especially of errors that seem to coincide with this issue.