Hmm....nothing here.

I never asked, but I assume, the redirection happens in Firefox?
If so...

Open Windows Explorer, and navigate to:
C:\Documents and Settings\<username>\Application Data\Mozilla\Firefox\Profiles\xxxxxxxx.default
Locate prefs.js file, zip it and attach it to your next reply.

Firefox is fine, but IE still has Yoog.

Close IE.
Go Start>All Programs>Accessories>System Tools, and click on Internet Explorer (no add-ons). Same thing?

For IE I just went to tools, clicked Search Settings, then deleted Yoog (default) and then reseted Google as the default search. I restarted my computer and it appears Yoog is gone from both Firefox and IE. Just alternative steps to fix the problem.

Very well, then.

One more thing...
You need to update Java:
Download Free Java Software - Sun Microsystems
JRE 6 Update 13
Uninstall all previous versions of Java through Add\Remove ("Programs and Features" in Vista).

Note
1. The Java Quick Starter (JQS.exe) adds unnecessary startup service. To disable the JQS service if you don't want to use it, go to Start > Control Panel > Java > Advanced > Miscellaneous and uncheck the box for Java Quick Starter.
Click OK and reboot your computer.
2. Make sure to uncheck Yahoo!Toolbar box during installation process.

IF no more problems....

1. Download, and install CCleaner: CCleaner - Builds. Get "Slim" version.
Read CCleaner instruction here: CCleaner Manual.
Run CCleaner.

2. Turn off System Restore:

- Windows XP:
1. Click Start.
2. Right-click the My Computer icon, and then click Properties.
3. Click the System Restore tab.
4. Check "Turn off System Restore".
5. Click Apply.
6. When turning off System Restore, the existing restore points will be deleted. Click Yes to do this.
7. Click OK.
- Windows Vista:
1. Click Start.
2. Right-click the Computer icon, and then click Properties.
3. Click on System Protection under the Tasks column on the left side
4. Click on Continue on the "User Account Control" window that pops up
5. Under the System Protection tab, find Available Disks
6. Uncheck the box for any drive you wish to disable system restore on (in most cases, drive "C:")
7. When turning off System Restore, the existing restore points will be deleted. Click "Turn System Restore Off" on the popup window to do this.
8. Click OK

3. Restart computer.

4. Turn System Restore on.

5. Make sure, Windows Updates are current.

6. If any Trojan was listed among your infection(s), make sure, you change all of your on-line important passwords (bank account(s), secured web sites, etc.) immediately!

7. Download, and install WOT (Web OF Trust): Internet Security | WOT Web of Trust. It'll warn you (in most cases) about dangerous web sites.

8. Read How did I get infected?, With steps so it does not happen again!: How did I get infected?

9. Let me know, how your computer is doing.

When I tried to install the update, an error message appeared:

"ERROR - JAVA(TM) INSTALLER: Download Failed: from = http://javadl-alt.sun.com/uESD7/JSCG...e1.6.0_13-cmsi, to = C:\Documents and Settings/NameofUser\Application Data\Sun\Java\jre1.6.0_13/jre1.60_13\jre1.6.0_13-c.msi"

Try to re-download it.
No other issues?

Originally Posted by broni

6. If any Trojan was listed among your infection(s), make sure, you change all of your on-line important passwords (bank account(s), secured web sites, etc.) immediately!

You mean Trojans that were listed in previous scans?

Yes.