Hi, I have purchased the Windows 7 Professional to update from XP. I did all the pre-purchase downloads and checks, and got all the ticks. When installing the 64 bit DVD, I get the following error message “This installation disc isn’t compatible with your version of Windows. To upgrade, you need the correct installation disc. For more information, check your computer’s system information. To install a new copy of Windows, restart (boot) your computer using the installation disc, and the select Custom (advanced)â€Â, don’t even get the option to custom install. I put the 32 bit DVD, custom installed and all worked OK. Put the 64 bit DVD and still get the same error. I am running 4GB Ram & 3.4GHz processor. Hoping someone can help as would really love to run W7 in 64-bit mode.