Try the slmgr /dlv command and if it is successful post a screen here. By any chance have you installed any crack like RemoveWAT or Chew7.
The slmgr command is not successful. The slui.exe message translates to Windows must be restored. An unauthorized change was made. I've run Windows 7 Toolkit 1.8 several times rearming w7 this year using up all the rearms. I used the option Remove all cracks in this Toolkit. I think that's the cause of the Windows must be restored message. I might restore my backup from february but only if this can't be resolved.
I restored a windows7 image which solved the slui.exe problem. The re-arming procedure described here just doesn't work for my system. I ran alll the steps again, after slmgr /rearm the msgbox says successful but the slmgr /dlv keeps stating that the product key is not found.
Running sfc command: Beginning system scan. This process will take some time. Beginning verification phase of system scan. Verification 100% complete. Windows Resource Protection found corrupt files but was unable to fix some of t em. Details are included in the CBS.Log windir\Logs\CBS\CBS.log. For example C:\Windows\Logs\CBS\CBS.log