There's a couple of things you can try for that.
These commands you may have already run, but if not.....
Recreate the Licensing Store
Go to Start > All Programs > Accessories
Right-Click on Command Prompt and select Run as Administrator - accept the UAC prompt
Run the following commands in the Command Prompt window, using the Enter key at the end of each
net stop sppsvc
(wait until the service has stopped before entering the following lines)
CD %windir%\ServiceProfiles\NetworkService\AppData\Roaming\Microsoft\SoftwareProtectionPlatform
REN tokens.dat tokens.bar
net start sppsvc
slui.exe
After a couple of seconds the Windows Activation dialog will appear.
You may be asked to re-activate and/or re-enter your product key, or Activation may occur automatically.
If you are asked for your Key, use the one on the COA sticker on the machine's case
Reboot.
Or this MS Fixit
http://support.microsoft.com/kb/2230957Or these commands run from an elevated command prompt - you can copy and paste these ones and they will auto run but if any appear to be sticking, just press enter.
net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver
ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
ren C:\Windows\System32\catroot2 catroot2.old
net start wuauserv
net start cryptSvc
net start bits
net start msiserver
Hope some of this will be of help in negating the reinstall.