There are two possibilities here - one should be a quick fix, while the other may take some time.
1) go to
www.microsoft.com/genuine/validate - what happens? If validation passes, you'll be offered MSE and IE9. If it fails, it'll be obvious :)
2) Your Licensing Store may be corrupt.....
Recreate the Licensing Store
1) Click Start button.
2) Type: CMD.exe into the 'Search programs and files' field
3) Right-Click on CMD.exe and select Run as Administrator
4) Type: net stop sppsvc (It may ask you if you are sure, select yes) Note: the Software Protection service may not be running, this is ok.
5) Type: cd %windir%\ServiceProfiles\NetworkService\AppData\Roaming\Microsoft\SoftwareProtectionPlatform
6) Type: rename tokens.dat tokens.bar
7) Type: cd %windir%\system32
8) Type: net start sppsvc
9) Type: slui.exe
10) After a couple of seconds Windows Activation dialog will appear. You may be asked to re-activate and/or re-enter your product key or Activation may occur automatically. Let me know what happens and we will continue on from there.