check youtube ,people wanting to change from 32 bit to 64 bit using same key
I don’t know if this will help. It worked for me.
Down below is your key and your instructions for downloading it. You can burn it to a CD, and do a fresh install if you want. Because this is an upgrade version, activating it after a fresh install takes a couple extra steps which are:
Open regedit.exe with Start Menu Search and navigate to:
HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE/
Change MediaBootInstall from “1” to “0”.
Close RegEdit.
Start Menu on the Command Line utility. Right-click this shortcut and choose “Run as administrator.”
Click Yes to the UAC prompt.
In the command line window, type: slmgr /rearm press enter
wait for the “Command completed successfully” dialog.
Then, close the command line window and reboot.
After Windows 7 reboots, Right Click Computer select Properties select change product Key.