X200 blinking cursor not booting

[orspgupp]

Hello all.

I recently got myself a mint condition ThinkPad X200 for writing. When it starts up, the ThinkPad logo shows, just like usual, but after that, when it wants to boot into an OS, like my Arch installer USB, it just shows a blinking cursor and does not move on. It also has this issue (just saying incase it's related), that when I make changes to the bios and hit "Save and exit", I just get greeted with a black screen and need to reboot. Changes do seem to be saved, but this, as far as I know, is not normal. It only boots into the Lenovo Bios Update CD, which I was able to execute and update my bios, incase that was the issue, but no. It too froze when it prompted me to press Enter to reboot. I suspect my bios is somewhat broken, but I have looked everywhere and spent hours trying to fix my problem without results, thus any help from experienced ThinkPad professionals on this forum would be appreciated.

Tech specs: C2D P8700, 4gb 1333 ddr3 ram, bios v3.22

[RealBlackStuff]

Welcome to the Forum.

You can get the X200 manual from the HMM-Manuals link above.
If you can, check the voltage of the yellow CMOS-battery, should be 2.8V or better.
If below, replace it.
Try this: remove the main battery, HDD/SSD and the RAM.
With only the charger, try to boot, if it beeps 1-3-3-1, the motherboard should be still OK.
Clean the gold contacts from your RAM stick(s) with an eraser, blow any eraser remnants away and put the RAM back.
Now boot and immediately press F1 to go into BIOS, press F9 (set Default options), then press F10 to save/exit.
Any better?
If so power off, put the HDD/SSD back and continue.

[orspgupp]

Welcome to the Forum.

You can get the X200 manual from the HMM-Manuals link above.
If you can, check the voltage of the yellow CMOS-battery, should be 2.8V or better.
If below, replace it.
Try this: remove the main battery, HDD/SSD and the RAM.
With only the charger, try to boot, if it beeps 1-3-3-1, the motherboard should be still OK.
Clean the gold contacts from your RAM stick(s) with an eraser, blow any eraser remnants away and put the RAM back.
Now boot and immediately press F1 to go into BIOS, press F9 (set Default options), then press F10 to save/exit.
Any better?
If so power off, put the HDD/SSD back and continue.

Still nothing. Done everything you listed, even made a CMOS battery at home (which should be good, being above 2.8v) but the machine still only shows a black screen with a blinking cursor. Also, for further info: the screen, when hitting F10 to save and quit, just turns black. No reboot, nothing. It also started doing this thing where upon passing the ThinkPad screen the image slowly fades white, starting from the edge of the screen. It looks spooky and makes me question the purchase of a new mobo
Although that is a very real option, I would like to fix this one I already have, because a new one would be quite expensive. Any enthousiasts whom had this issue? If so, help is appreciated.