The problem has become so great, a consortium of vendors have set up the Conficker Working Group to deal with the malware's spread, and Microsoft are offering a $250,000 reward for the identity of the writer.

Naturally, you should be running an up to date anti-virus. Most widely used AV programs will do the job, including Open Source detectors like Clam AV and freeware programs. Note though that the licences for freeware programs like AVG and Avast! are specifically for home use only.

If you are running those on your office system, respect the developer's right to make a living and buy a commercial licence, they are actually cheaper and more reliable than many of the better known brand names.

Finally, make sure your users log on in Limited User mode. The reason why Windows computers are more prone to viruses than their Mac and Linux cousins is because most users run their Microsoft systems as the powerful Administrator mode which is the equivalent of leaving your car doors unlocked all night. We have some instructions on setting up Limited User Profiles for Windows XP systems on the PC Rescue website.

If you have an office with a Windows 2003 or 2008 server, your IT department or consultant will be able to do this through the network, which is a lot more secure way of doing things.

Be warned that some programs won't work unless they run in Administrator mode. If you find this is a problem then you should consider replacing that software as the vendor has shown they are either incompetent or are prepared to put their customers at risk to save a few dollars. Either way, you don't need suppliers that have no respect for their customers.