Microsoft has already detailed the Windows 8 upgrade route for those buying a new computer, and it's now finally confirmed what everyone else will be paying when they upgrade their existing PC. Those running Windows XP, Windows Vista, or Windows 7 will able to download a Windows 8 Pro upgrade for just $39.99. That's a far cry from the company's earlier upgrade prices, which as recently as Windows 7 ran $50 and $99 for Home Premium and Pro upgrades, respectively. You will have to pay a bit more if you want packaged DVD version of the upgrade, though, with it running $69.99 at retail -- it also sounds like both of those prices will be going up when the promotion ends on January 31st of next year. Not surprisingly, the upgrade process will vary depending on the OS you're currently using. Those making the jump all the way from Windows XP will only able to bring their personal files with them, while those on Vista will be able to bring their personal files and Windows settings, but no applications. And, if you're wondering about Media Center, it will be available as a free option once the upgrade is finished.