killkingkong

Since removing the cmos hasn't gotten rid of the password you should try a blind bios reset. I found this guide on another forum, but don't know the rules for posting links here, so I'll quote. The quote is referring to the official bios versions given by dell/alienware. Also, if you want the 765m to work in your m18x r1 you'll have to then upgrade to the A05 bios, which can be found here.

If it were a bios issue I think you would just see a blank screen on boot, no post (I'm experiencing this right now). I think it's the drivers in windows stopping windows from booting fully. Since you already took your old gpu out, try reflowing it and getting it working, boot to windows and install the correct drivers.

If you're sure this happened after changing setting in the bios then removing the cmos battery for a few seconds should reset your bios to the default and get rid of your problem. I know you said it shuts down after 2 seconds, but have you tried f2 before it shuts down to see if it brings you back to the bios so you can reset? If not then just remove the cmos batter.

If there was water damage to the main keyboard it may be possible to effect the side keyboard. I've noticed that when water is spilled on keyboard they sometimes send the wrong keystroke that conflict with other keys. Do other people have access to your computer who may not be telling you something?

From what I understand A05 seems to be the highest number unlocked.