Stout92 :
but it can be done using an upgrade disc, not the full version? also, i don't quite understand. are you saying i can upgrade windows, then transfer the os to another hard drive?
What you cannot do is do an in-place upgrade where all your currently installed programs remain installed and it basically upgrades your Vista to Windows 7. If you were upgrading to 32-bit Windows 7, you could an in-place upgrade where you would NOT have to backup user profile data and restore and all your programs you had installed under Vista would remain intact.
But, because you want to go to 64-bit Windows 7, you cannot do an in-place upgrade. You will have to backup the user profile data, reformat the drive, and install Windows 7 64-bit. Then, you restore the user profile data and then you would have to go and reinstall all your programs that you had under Vista.
The reason being is because you cannot guarantee that all programs that worked under 32-bit Windows will work with 64-bit windows due to drivers having to be all 64-bit. That is one thing you'll need to really check is if all of your current hardware has 64-bit drivers for Windows 7. If not, if they at least have 64-bit drivers for Vista, then you're good to go. Otherwise, if only 32-bit drivers exist for your hardware, those pieces will not work under 64-bit Windows.
Remember, going from 32-bit to 64-bit is an architecture change, so it requires different drivers and software. You CAN run 32-bit programs under 64-bit Windows, but not 16-bit programs and you cannot use 32-bit drivers.
An upgrade disk for Windows is no different than the full version of Windows. The only difference is, with the Upgrade disk, you are using a previously licensed version of Windows (in this case, Vista) and you are transferring that license over to Windows 7, which makes the previous copy of Vista no longer legal (legally, you cannot install it on another computer and use it because the license has been transferred to Windows 7).
With the full version of Windows 7, you are purchasing a completely new license for Windows. Therefore, if you go that route, then your previous copy of Vista is still legal.
However, either version of Windows 7 (upgrade or full) allows a complete install. And as I stated, in the case of your wanting to go 64-bit, a clean install is your only option.