A bloke was telling the boards that he visited microsoft.com using IE4Linux, here, and tried to download Windows Defender, on Xubuntu.
Microsoft asked him to do the Genuine Advantage test, and he used used the alternate authentication method because IE4Linux doesn't support Active X.
He downloaded and then ran the genuine advantage application. This gave him a code that he pasted into the authentication box, and to his surprise it verified him and forwarded him to the download page.
He has posted a video of him doing it, if you are interested in watching stuff like this. ยต