1. Use regedit and goto
\HKEY_LOCAL_MACHINES\SOFTWARE
\Microsoft\WindowsNT
\CurrentVersion
\Winlogon\Notify
delete folder "Wgalogon" and all the contents
2. set your system folders to unhide Folder view or you won't see dllcache folder
3. go to c:\windows\system32,
rename WgaTray.exe to WgaTray.exeold
rename Wgalogon.dll to Wgalogon.dllold
4. go to c:\windows\system32\dllcache, rename WgaTray.exe to WgaTray.exeold