in 2009 I purchased a Dell leptop which had Windows VIsta installed. I hated Vista, so I bought Windows 7 Ultimate 64 bit from a reputable supplier, and installed it. This was in May 2010. I registered it immdeiately after installing. Everything has been working fine until last week. I got the "Windows 7 BUILD 7601 THIS COPY OF WINDOWS IS NOT GENUINE" message. I tried to revqalidate with the orignal MS key and get the message "This key is blocked by Microsoft". I have called Microsoft and the only thing they tell me is it is not a genuine version, that I have been a victim of software piracy. How after 3 1/2 years could this be. Any help would be apprecitated. maxemax@earthlink.net.