Invalid Product Key when installing on new SSD

If there is any OS on the HD the installer will see it at boot and allow use of Upgrade version key during install. If none then it requires doing one of the two workarounds given in Clean Install with a Upgrade Windows 7 Version tutorial. Which one did you do?

Easiest is this one:

OPTION THREE
Clean Install with a Registry Workaround for Error Code 0xc004f061

Note
If you get a activation error code 0xc004f061 while doing OPTION ONE or OPTION TWO above, then you will need to use this option instead documented by Paul Thurrott's Supersite Blog: Clean Install Windows 7 with Upgrade Media.

1. Do a clean install of your upgrade Windows 7 at boot without checking the Automatically activate Windows when I'm online box during the installation process.
NOTE: If you already did this from OPTION ONE above and got a activation error, then skip this step and just proceed to step 2 below instead. There's no need to reinstall again.

2. Ensure that there are no Windows Updates pending that would require a system reboot to finish installing. (You'll see an orange shield icon next to Shutdown in the Start Menu if this is the case). If there are, then restart the computer to let them finish installing before proceeding to step 3 below.

3. Click on the Download button below to download the MediaBootInstall.reg file, and save it to your desktop.

4. Double click on the downloaded MediaBootInstall.reg file to merge it, then approve the merge.
NOTE: This will change the MediaBootInstall value from 1 to 0 at the registry location below automatically for you.

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\OOBE

5. Open a elevated command prompt.

6. In the elevated command prompt, type slmgr -rearm and press Enter. (See screenshot below)

7. Click on OK. (See screenshot below)

8. Close the elevated command prompt, and restart the computer.

9. When the computer is finished restarting, then manually activate Windows 7 with your product key number.

Quote: Originally Posted by Pual Thurrott
The method described above should work for just about anyone, with the understanding that any pending Windows Updates could screw things up. If that happens, just shut down, restart, rerun the command line sequence (steps 5 to 8), and retry activation.

If activation doesn't work then the main cause is inputting incorrect digits. Triple check what you type before sending it.

If that fails try phone Activation using the link I gave earlier.

There is no reason to install Vista.

To check that the Reg file you downloaded and Merged as instructed changed the Registry value correctly, type Regedit in Start Search box, rightclick on result given to Run As Administrator, browse to the path shown on the bottom of the Window in step 4 after clicking to enlarge it.

Once you verify the Registry Edit was made, you'll need to run the Elevated command in Step 5 and then you can Activate at Computer>Properties link.