Next time this happens simply go to start > run > and type in shutdown /a or shutdown -a. This will stop your computer from rebooting.
BTW this is a virus.
At least thats who started it.
See here for all the info u need. Right from Microsoft.
hxxp://www.microsoft.com/security/incident/blast.mspx
Or just download the fix right here.
hxxp://www.microsoft.com/downloads/details.aspx?familyid=e70a0d8b-fe98-493f-ad76-bf673a38b4cf&displaylang=en
Yeap good old Blaster Worm. lol
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