1. Reboot your computer. While the computer is starting up again, hit the 'F8' key to bring up the boot options. Select 'Safe Mode.'
2. Click the 'Start' button and choose the 'Run' option from the Start menu. Type 'regedit' in the Run window and click 'OK.'

3. Search the Registry Editor for the 'wgalogon' folder and delete it. Select the 'Search' option from the Start menu and use it to find and remove any other 'WGA' files.
4. Reboot your computer normally.