Could it be possible that your mobo battery is on the way out?
I had to replace mine recently following 'ntldr missing' error during bootup - the bios was reset to default, so didn't know which drive to boot windows from.
You could reset it in the bios then load windows, but the next time you switched off it would revert back to default. Lost time and date too which made my all programs list on the start menu think it had all new applications highlighted
