You cannot upgrade between 32ibt and 64bit. It requires a fresh installation. It sounds like this is recent so I suggest you reinstall with the 64bit dvd while it is still relatively easy to do it. There is little to recommend 32bit Windows
anymore. The world has moved on.
This is the wrong forum for this subject, however. This forum is for fixing non-genuine problems with Windows, not for installing it. Please use the Answers Windows 7 Installing, Upgrading, and Activating forum at
http://answers.microsoft.com/en-us/windows/forum/windows_7-windows_install?page=1&tab=no
Colin Barnhorst Windows 7 Ultimate x64 on DIY with 6GB ram.