On boot, computer "restarts" then gives me infinite black screen

[Gnome Ercy]

When I press the power button on my computer, it boots up, then turns off for about 3 seconds, and then starts up again. I have no picture at all right now - but I just installed a new video card (was having the problem prior) and was able to boot a few times with it. Things were going great, then had to restart to install some updates, and then it all went south. Now it's just all sorts of messed up. Don't have any spare parts laying around, and don't want to invest in a new computer at this time. I can't get to BIOS or anything to even suggest reinstalling Windows or change any settings.

Am I SOL?

Note: The computer had been off for about two months, and is five years old. It's about time for a new build, I just don't have the money for it right now.

 

[Melderv]

I'm hardly sure what the problem could be but I'd start looking for a new MOBO, then if that doesn't work, new RAM.

 

[Gnome Ercy]

I ended up buying a new build anyway (no interest/no payments for a year), I'm going to probably end up swapping out compatible parts to see if I can diagnose the issue.