I have a several year old computer that came with WinXP pre-installed. At some point I upgraded to Vista and more recently to Win7. Then I had a hard disk failure and had to start over with a new drive. I don't have the original WinXP disk, so I installed Win7 directly. The normal activation process won't work, of course, since there's no previous version of Windows on the computer. I have the product key for the original WinXP (from a sticker on the computer case), plus keys for the Vista and Win7 upgrades. Who do I contact at Microsoft to activate my legal Win7 product manually? Thanks.