There is a weakness in later versions of Windows (2000, XP etc) that people have just discovered and are using it to take control of computers and load the W32.Blast.Worm virus.
Fix for the virus is here:-
http://securityresponse.symantec.com...oval.tool.html
The MS patch Fix to close the RPC loophole is at:-
http://www.microsoft.com/technet/tre...n/MS03-026.asp
More info at:-
http://www.thetechguy.co.uk/comments...atid=1&id=1321
FWIW, my version of Norton Internet Security (as updated) catches the virus, but can't close the lophole.