My Acer notebook had geniune windows 7 installed and working fine. I upgraded to windows 10 and still worked fine for some time and then it started to get stuck at start up. There was a continous beep while windows was trying to load but it will boot up after 3 4 minutes and faster if I interupt by pressing any key. I have disassembled my laptop for cleanup and replacing the screen earlier and checked for loose RAM or a stuck key. There were none. Then it got stuck at boot device selection menu without booting windows. I used the recovery CDs to put back windows 7 (I wanted it back) to see if reinstalling an OS would fix any disk errors. Now the beeping is gone but still does not boot directly into windows but I have to manually select boot device each time at startup. tried startup repair and it says there are no errors. Checked disks using chkdsk. Tried fixmbr and nothing happened. Please help.