Need help removing trojans and spywares

I'd like to know how to remove safely those trojans or spywares. Here is the result of a recent drive scan from stop-sign.com

status file Virus or threat:
infected CoolWebSearch Software Package possible spyware application
infected ClickTillUWin software Package possible spyware application
infected Virtuamondo Newtonnows Application possible spyware application
infected Walnut ventures 2020Search Toolbar Software package possible spyware application
infected C:\msinfo.exe Trojan.downloader.500
infected C:\hp\bin\Terminator.exe Trojan.KillApp.30208
infected C:\programfiles\internet explorer\cqrmxkue.exe Trojan.downloader.500
infected C:\Documents and Settings\Default User\LocalS.. Trojan.downloader.500
infected C:\Documents and Settings\Default User\LocalS.. Trojan.MulDrop.959
infected C:WINDOWS\system32\config\systemprofile\Lo.. Trojan.downloader.500
infected C:WINDOWS\system32\config\systemprofile\Lo.. Trojan.MulDrop.959

Files\Content.IE5\8KZRVZFA\msits[1].exe is infected with: Trojan.downloader.500
Files\Content.IE5\HJ4MG4LI\main[1].chm is infected with: Trojan.MulDrop.959
Total threats found: 7

Has anyone seen those before and is there a free software out there that can help? I don't want to remove them manually because one of the infected file (msinfo.exe) is a MS system file.
Thank you

 

Hello

It wasnt very long ago when we saw stopsign in log we fixed them,
But according to the page here they have changed there ways,
http://www.spywarewarrior.com/rogue_anti-spyware.htm#ss_note

Franky i would let it near my pc, stick with Ad-Aware SE , SpyBot and now the new MSantispyware programs to clean up and help prevent Spyware.

Clear your temps:
Delete the contents of all your temp folders, as in. Open C:\ then >
C:\documents and settings\(all your pc users)\local settings\temp
Note: Some systems have temporary internet files, Application Data and History in that temp, if so leave them and delete all other folders and files inside that temp..
Delete the contents of the C:\windows\temp folder
C:\WINDOWS\Prefetch < delete the contents
C:\WINDOWS\SYSTEM32\config\systemprofile\Local Settings\Temp <delete the contents
Clear Internet Explorers's cache
1. In Control Panel, open Internet Options.
2. Click the General tab, and then under Temporary Internet files, click Delete Files.
3. In the Delete Files dialog box, click to select the Delete all offline content check box.
4. wait for the hourglass to disapear
5. Click OK.

Post a hijackthis log provided its the latest version 1.99.1