Avirus has just hit the internet networks all around the world. please goto http://www.microsoft.com" rel="nofollow">LINK to see updates for prevention, before its too late.
the virus just blocks your access to your network connections and the internet. and everytime you acces them it just restarts the system.

if you are hit by this virus(actually its a worm), please goto windows folder-->then system32 folder -->and try to locate and delete the msblast.exe file. it may not let you delete the msblast.exe file so try to delete it from DOS mode if available from your operating system. Otherwise restart your computer from a bootable floppy and try to delete the file.

regards