help please

[Trev]

i have just refofmatted my drives & reinstalled XP, but
now i keep getting a box come up saying " SAVE YOUR WORK
WINDOWS IS SHUTTING DOWN NT AUTHORITY\SYSTEM " THEN THE
PC SHUTS DOWN what's causing this. can you help please?

 

[rifleman]

i have just refofmatted my drives & reinstalled XP, but
now i keep getting a box come up saying " SAVE YOUR WORK
WINDOWS IS SHUTTING DOWN NT AUTHORITY\SYSTEM " THEN THE
PC SHUTS DOWN what's causing this. can you help please?

You probably are infected with the Blaster virus.

Go here: http://www.microsoft.com/security/incident/blast.asp