Win 10 back to win 7 and win 7 will not run. I have a dell 64 bit machine that downloaded and installed win 10. The customer wants it back to win 7 and it was within the 30 day window. It was a successful operation, however win 7 will not start. I have started in safe mode, but there is no keyboard or mouse available. I have tried other repairs with no success . Any help would be appreciated.