The least I can do is tell you to open up regedit in safemode, go to HKEY_CURRENT_USER => Software => Microsoft => Windows => CurrentVersion => Run and look for random lettered executables that point to %AppData% folders and Windows folders such as System32. Check HKEY_LOCAL_MACHINE (Including the sub-categories, CurrentVersion => Run etc) as well for the same thing.
Whatever you do, don't start removing registry entries, just take a screenshot of it and post it here. if you remove random entries then your computer will not work.
http://en.wikipedia.org/wiki/SystemRescueCD with anti-malware should do it but it takes time to set up.
Checking Task-manager privileges
HKEY_CURRENT_USER => Software => Microsoft => Windows => CurrentVersion => Policies => System => DisableTaskMgr (double click on it), you'll find it's been turned on.