Just one link here to problem to get you started >http://tinyurl.com/7fcsk

Affecting Windows 2000 and prior versions. Recommendation to shut PC down. MS had patch offered the other day (I think)

UPDATE:
It appears it is not the Zobot worm but a variation, titled underscorezbot.e.bq (something like this).
Excellent free scan at http://housecall.trendmicro.com/ And get patch from Microsoft
Called a low impact but has affected CNN PCs in NY and Atlanta, NYT and ABC News and Asia.