Microsoft has admitted to unwittingly pushing malware-infested adverts on users of its Windows Live Messenger program. The infected banners within the instant messaging software included those advertising Errorsafe , a program which claims to fix computer system errors.

This software is infamous because it attempts to slyly install itself onto the computers of unsuspecting computer users, using the SysProtect vector - a small piece of software which spreads viruses. Once installed, it misleads users into believing the computer has virus problems and prompts them to buy the full version of the program in order to fix the errors.

"We apologise for the inconvenience and are reviewing our advertisement approval process to reduce the chance of an occurrence such as this happening again," said Microsoft in a PR announcement.

It was a serious blunder for Microsoft to allow the Errorsafe banner advert into the Live Messenger system, and there's no word yet on how many instant messenger users were caught out by the ad.

It's possible for users to strip out adverts in Windows Live Messenger, as well as customise it in ways that the original Microsoft build does not allow. All you have to do is download and install the A-Patch .