You likey have a virus.
For additional help see
www.dougknox.com, Win XP Utilities, Create Emergency
Copies of Critical XP System Utilities. This small VB Program will create
backup, usable copies of Task Manger, Regedit and MSConfig (named
Copy_of_Taskmgr.exe, Copy_of_Regedit.com and Copy_of_MSConfig.exe) in a new
folder C:\EmergencyUtil. Many virus programs will intercept these programs,
based on their original file name. The modified file names, allow them to be
run. Open Windows Explorer to C:\EmergencyUtil and double click the
application you need.
Additionally, see the Win XP Utilities section for Startup Programs Tracker.
This small utility scans your system for startup programs and running
processes. It also allows you to create a log file that can be copied and
pasted into a newsgroup post. The contents of the program window are also
copied to the Windows Clipboard, automatically. For replies to newsgroup
posts, do NOT include the Running Services, unless its absolutely necessary.
In some cases, it is necessary to rename the emergency copies, so they don't
contain the taskmg, msconfig and regedit in the actual file name. Virus
authors are getting smarter and are doing pattern matching to find even a
partial match.