I'm sorry if there is already a thread on this issue, but I couldn't find one. I have been happily running Win7 RC under Snow Leopard and Parallels 4 (latest build). I also have a Guest OS running WinXP. I have preordered the Win 7 Upgrade which will be released next week (finally)! I am planning on installing it on my XP guest VM as Microsoft requires a licensed version of Windows in order to use the upgrade (as opposed to the full edition which is much more expensive). So my question is, will I be able to upgrade my XP to Win7 VM since Parallels still has only "experimental support" for Win7, and will there be any problem with the XP machine configuration becoming a Win 7 configuration (I have enough virtual disc space 40 GB and enough RAM already on my XP machine). I realize I will have to do a "clean install" so I have already purchased the LapLink PCMover Upgrade Assistant to transfer my files and programs. I'm sure this will be a big issue next week when the retail Windows 7 OS is released officially. Perhaps you parallels guys could post a "sticky" with instructions on how to do this upgrade?