Windows 7: Installing Win 7 on same computer with new harddrive

My problem in a unique one. I installed Windows 7 on my computer back a few months ago, using the given product key. Since that time, though, I have had to install a new hard drive on my computer. I wasn't able to retain any of the data from my old harddrive -- it was a fresh start. I've installed Windows 7 on this new harddrive with the same disk, but now the product key won't work, because I already used it when I installed it last. I'd rather not have to buy a new copy of Windows 7, considering I'm not installing it on multiple computers. I'm installing it on one computer. I just didn't uninstall it when I replaced my harddrive. Any suggestions? Do you think Microsoft would be able to revalidate my product key?

When you say it won't work, do you mean activate? If so, just select to activate by phone and explain what you did to the Microsoft rep. It usually takes 5 minutes.

Hello LMcLaughlin09 Welcome to the Windows 7 Forums!

One question right off would be the type of 7 full version retail or OEM or upgrade disk you are using there?

Assuming that you do not have the OEM edition, you can install it on another computer; only one at any given time.
Install in the normal fashion. When asked for your key, do not give it; rather complete the installation. When done, install your programs and then use it for a while. If you are happy with the setup, activate by phone. You just need a push button phone for this procedure. If it does not work, you will be transferred to a technician. This is not a problem, be honest tell him what you told us and you will be ready to go.

An OEM disk is generally a full install disk as well but limited to one machine only. If an upgrade disk was used on a new drive that would immediately run into activation problems.

I would not think that just a HD change would trigger it. I know a MB change will and possibly changing a few components at the same time might. Interesting though.

I have the 64bit edition installed first on one 500gb drive and just added a new larger host drive in for the second 64bit install there. I also have the 32bit set up on a 3rd drive with each activated.

If you have the retail full version disk you shouldn't be running into problem unless you saw a bad install or are mistyping one digit in the product key. That will do it every time!

pbcopter was correct there about calling the toll free MS number and reading off the 8 sets of 5 digits to the op or automated voice if you had already been activated and a hardware change caused a reactivation prompting. You can still try but..... ?

Activate at Computer>Properties link. It may require a robo call to MS but will activate after deactivating on old hardware config. Unless it's OEM.

When just this past week having added in a larger drive for the 64bit Windows I had to decide which of the other two OSed drives(one with the 64bit RC, the other with the retail 64bit) would be used for the 32bit 7. The 32bit was needed for a very few old XP apps and the RC could now go solved that one fast.

The two fresh installs one of each activated immediately as the 32bit added the new 64bit install into the BCD while ignoring the first 64bit on the smaller drive. The only thing that comes to mind right off about not being able to activate the installation you have there is the installation method or simply a bad install where something needed didn't unpack like it should have.

Since the product key worked the first time around you also still have to consider a mistyped digit unless the new drive itself has a defect? Also inspect the disk itself to see if you missed a new scratch or smudge from handling it. You have to retrace your steps a bit.