W7 32bit to 64bit

Hi guys I've did a bit of searching but cant find the info i'm looking for.

Basically I currently have the 32Bit of Windows 7 Professional on my PC (I was really sure I had 64!) so when I've come to install 4Gb of ram it only shows 3.2...
Can I just pop in a W7 Pro 64bit disc to upgrade with my current CD Key? Or do I have to buy it again?

Though I think I'd rather do a wipe and clean install, so would that be okay? I wont get bothered with any "this key has already been used" messages will I?

Thanks in advance :)

You can't upgrade from x32 to x64, a clean install is required
Clean Install Windows 7

Cheers for the 'super-special-awesome' fast reply

I'll do it straight away

It's not clear from reading the thread what sort of license Wezness has.

If it's a retail full or upgrade license, there's no issue with switching from 32 to 64 bit.

If it's an OEM license, it may still be poosible to use the original key to activate the 64 bit version, but coming up with installation media may be a bit more of a challenge. (I have no personal experience with this - my licenses are retail.)

Yeah, I agree...it definitely wasn't clear in terms of licensing. If you have an XP license (retail), then it could be reused on another computer. It has nothing to do with the new Windows 7 license. When you install that on the computer, it will be considered in use, and can't be used on another computer at the same time. The disc is just a disc...contains no licensing info, so you could use it a thousand times if you wanted. If you've already used the Windows 7 key on another system, you'll need to buy a new license.