I am having this problem as well and under start up & recovery there is no OS options to select for default.
The computer started having virus/malware problems, so I started to try removing programs(tool bars and other unnecessary things) and clean it up. After getting it to boot into safe mode and then trying to make it do a clean boot it now will only go into safe mode. F8, to try start up repair does not work, it will not load. You cant select normal mode as it keeps going to safe mode. In msconfig it is not set to boot into safe mode, normal mode is selected. I have tried system restore, last known good config, sfc /scannow, chkdsk /r. I am trying to avoid reinstalling Windows but it seems options are running low...
One thing to keep in mind is that I am trying to fix this over the phone and remoting in when possible.
Appreciate any help!