Taskmanager problems

Hi Newbie here
Whenever I try to access taskmanager it displays administrator has disabled taskmanager. I haven't and there is only one account on my comp. When I did a search for Taskmgr.exe I found 2 files, taskmgr and TASKMGR.EXE-06144C13.pf which is a prefetch file. I accessed the registry and set prefetch files to disabled but it had no effect so I put it back as I found it set on autolaunch and bootlaunch. I am stuck, can anyone help?
Regards
Lyn

A search (http://www.techspot.com/vb/search.html) on Task Manager problems results in about 300 threads...

You could do the same as countless of other people: download HijackThis (http://www.merijn.org/downloads.html) and post its logfile here.