You may need to pull the bios battery to reset the bios.
Disconnect the AC from the computer.
Open the case
Look for the battery and remove it. Be careful you don't break the battery holder.
Leave the battery out for about 5 minutes.
Reinstall the battery
Connect the AC
Start the computer and try to enter bios again
Read the online documentation HERE
. There are sub-links to how to do everything you need to do. Be sure to read the first link on the page... Before you begin
If resetting the bios doesn't help, then you will need to start doing some heavy hardware troubleshooting... like removing ram modules, and such.