PC users are bracing themselves for the latest virus, one so menacing that Microsoft has offered a reward of a quarter of a million dollars for tracking down its creator, which some experts believe will strike on Wednesday April 1st.

The Conficker virus is reported to have infected 10 million computers and experts believe that the April Fool's Day is D-Day. Just what the virus is going to do is not entirely known, ABC Online reported on Tuesday.

On April 1 a master computer is scheduled to gain control of these zombie machines, said Don DeBolt, director of threat research for CA, a New York-based IT company.

Microsoft offered a $250,000 reward for information that results in the arrest and conviction of those responsible for illegally launching the Conficker malicious code on the Internet, the company said in a statement released last month.

This computer worm infiltrates your PC over the internet or by a USB connection. Once it is in your computer, the Conficker C worm digs deep and tries to hide. Its purpose remains a mystery with experts only assuming the possible purpose.

Michael Conway of Renaissance Contingency Services says; We simply don't know what it is designed to do yet. It may be asked to do things, take information on Credit Cards, take other information.

The program could delete all of the files on a person’s computer, use zombie PCs — those controlled by a master — to overwhelm and shut down websites or monitor a person’s keyboard strokes to collect private information like passwords or bank account information, experts said.

DeBolt also foresees the virus may try to get computer users to buy fake software or spend money on other phony products.

Symantec warns that on Wednesday, Conficker “will simply start taking more steps to protect itself.”

After April 1, machines infected with the new Conficker strain may not be able to get security updates from Microsoft and other security products vendors, it says.

There are some easy ways to figure out whether a computer has the Conficker worm, and free tools available for getting rid of it. Visit the site here to download the tools.

What's quite nasty about the Conficker is that it spreads without human involvement, moving from PC to PC by exploiting a security hole in Microsoft Corp.'s Windows operating system. The hole was fixed in October, but if your computer doesn't get automatic updates from Microsoft, you could be exposed.