Try the following solution to your problem:1. Power off your computer
2. Power on your computer -> then Keep tapping F8.
3. Select Repair my Computer -> System restore
4. Select the restore point prior to the Service Pack 1 updates -> Start restoring
5. The process can take some time, so wait until it completes. Ignore it if it fails and didn’t change anything, because it will boot anyway.
6. Try install the service pack all over again by going into Windows Updates.
Hope this helped you out.