Post a screenshot so we can see what you're referring to. Could be an OEM or a Microsoft thing.
Is this the 'Windows is not genuine" popup? Have you changed your product key for Windows or reinstalled the system lately? That usually happens with OEM reinstallations and is often solvable by using the phone activation solution, i.e. phoning Microsoft to activate.
Of course even that wont work if the key is not genuine.
You can tell if Windows is activated correctly by right-clicking 'Computer' on the desktop or in the Start Menu and selecting Properties, then scroll down to the bottom. (My Computer in XP)
If it's malware by the above name there is a tutorial here: http://malwaretips.com/blogs/genuine-microsoft-software-virus/