OK lets do this, we are going to do a hard Clear CMOS. That will ensure that no corrupted or scrambled BIOS stuff is present to mess up your post process.
I would like you to remove all the components from your system.
Start with all the PSU cables
Then the hard drives and VGA cards
And finally the battery
Now press power for a few seconds this will remove any residual current from your system.
Clear CMOS button on the in/out panel for 5 secs or so.
Leave to stand for at least 2 hours, it would be better over night
Rebuild and boot up.
To help us help you - please provide as much information about your system and the problem as possible.