Normally I would never post anything like this (in fact we have a strict policy in work to never forward mails about viruses) but a load of my friends have been getting unsolicited calls from tech support claiming that they're calling on behalf of Microsoft, and that there's a problem with their pc.
Either they ask for your online banking details, or they ask for your credit card details, to fix the issue remotely. Of course, there is no issue, and they'll just clear out your bank account/credit card.
If you get this call, ignore it, hang up, or just put the phone down until they hang up.