ok. C:\windows\system32\taskman.exe is a legitimate windows file (unless it is altered ofcourse) and should show if you navigate to it through explorer (=my computer)
Visit
JOTTI and type (or copy/paste) C:\windows\system32\taskmon.exe and hit the submit button. What happens? Getting an error? If so, what is the error?
Also let me know how you installed XP. Was it a upgrade from windows98? A clean install?
And last (for now) right click my computer, properties an look at the number there.
It will look like: XXXXX-YYY-YYYXXX-XXXX
Tell me what is says about the YYY-YYY part