Before this I also having this problem when repairing pc's so you need to follow the step below to start safe mode after to configure you pc. It should be solve your problem.
1. Click start
2 .Click run
3. Type msconfig and hit enter
4. Click the radio button for Diagnostic Startup
5. Click apply and close
6. In the dialogue box that appears click restart
7. When windows restarts you will be in safe mode
8. Minimize the window and run your programs
9. When you are done, go back to normal startup.