Just like a console man to take the easy way out
Just run explorer.exe, go to Tools/Folder Options, select the "View" tab, then enable "Show hidden files and folders". Now go to C:\WINDOWS\SYSTEM32\. You'll notice a file called "taskmgr.exe". This is the windows task manager. Now if there's a virus that is shutting down taskmgr.exe (and those DO exist), the solution is to select that taskmgr.exe, press ctrl-c to copy it, and press ctrl-v in the same directory to make a copy of it, named "Copy of taskmgr.exe". Rename this file to something innocent like "blah.exe". Note that the .exe extension will usually be hidden in Windows, so you can use "blah" and "taskmgr" instead of "blah.exe" and "taskmgr.exe" everywhere. Now if you start this "blah.exe", it will have that name in the process list, but it will still be the task manager. Most programs that try to kill a specific process like taskmgr.exe will look for that specific name, so any change of that name should dodge their attempts. If you can run "blah.exe", you can be almost 100% sure that you've got a virus. Most virusses of late have a long list of process names of antivirus software and other programs that they kill so they (the virusses) cannot be easily killed themselves.
Capisce ?
Or, you can take the console way out and do a system restore. But that's not a manly way to do it
PS Don't forget to use
this free and easy to use online virus scanner. You can use it without having to download and install another program.