I don't know if it is said before, but if "windows" sais such things you can track down the message. I don't realy know how but it is possible. And I would recommend adaware

i've been using it for a couple of years and my PC still works!!
And if nothing is working try to double click the logo in the right part of the start bar.....then you should enter the code that's on the official sticker that's on your pc(mostly at the back) from microsoft......
Hope it helps!!
I had the same problem, that was because I had to "reset" my pc after an hardware failure

Then I downloaded the newest update of windows(wich has an piratery check) after i entered the code the message disapeard. And I wasn't the only one having that problem. The microsoft site thing had an message about it a while ago