Are you referring to msblast or one of the Blaster Worm variants?
If so, Go to Start | Run | enter "taskmgr". When Task Manager launches,
click the "Processes" tab, locate the file called msblast.exe in the left
column "Image Name", click it once, then click the End Process button on the
bottom. When it disappears from the list, go delete msblast.exe from your
system.
More information on the Blaster Worm is below.
"What you should know about the Blaster Worm:
http://www.microsoft.com/security/incident/blast.asp
826955 Virus Alert About the W32.Blaster.Worm
http://support.microsoft.com/?id=826955
823980 MS03-026: Buffer Overrun in RPC May Allow Code Execution
http://support.microsoft.com/?id=823980
--
Andy
This posting is provided "AS IS" with no warranties, and confers no
rights.
=====================================================