Microsoft put out a warning today along with results of a survey about crooks doing cold-calls and scamming ordinary users.

MS surveyed 7,000 computer users in the UK, Ireland, US and Canada and found between 16 to 26 percent had received calls from "Windows or Microsoft Tech Support". Out of those, about 20% were actually tricked into giving the crooks remote access to their PCs, downloading dodgy code or even giving credit card info to make purchases.

Microsoft said if someone calls you: "Do not purchase any software or services. Ask if there is a fee or subscription associated with the 'service'. If there is, hang up." And if you did get duped, change your passwords and scan your PC to remove any viruses asap!