Is your friend telling you that you keep sending them links (website, image links etc.) that contain viruses? Or you accidentally clicked the virus link sent by your friend and afraid your MSN Messenger/Windows Live Messenger has been infected by the virus? Uninstalling of the software doesn’t seems to solve the problem?
Don’t worry. You doesn’t require to format your whole computer in order to kill the viruses. There are several free software out there is available for you to kill those nasty viruses for you.
Both software work well under Windows XP and Vista. Both should be working on Windows 7 as well (not tested thoroughly though). Hope they are able to help you in removing the nasty MSN/WLM viruses. And a piece of advise, don’t click on the links or similar if the links look suspicious to you. Always check with the sender whether the link was sent intentionally.