Security watchdogs warn that millions could be affected by the Conficker worm tomorrow – unfortunately this is not in an April Fool’s Day joke. Over nine million PCs are already infected and a new variant of the virus could threaten those who didn’t patch their PCs with the latest security updates.

Symantec warns that on April 1st Conficker “will simply start taking more steps to protect itself.” After tomorrow, machines infected with the new “C strain” of Conficker may not be able to get security updates or patches from Microsoft and other security products vendors, says the company. Known also as Downadup or Kido, Conficker is a worm whose purpose security researchers couldn’t decipher yet.