I have 2 hd's and dual OS, win7 and now win 10, each on seperate hd's. I then connected my win 7 hd, which i had disconnected it in order to install win 10. Then i went to the Bios to try and remove my usb boot up driver, and i just could,'t find this time, so i checked the csm compatilbility module and set it at Auto. I took a stab at it thinking it would override my usb boot.,then i started the computer and nothing appeared, this was after i had reconnected my win 7 hd. I cannot get into bios, to undo what i did. Any suggestions would be helpful and appreciated.