Question Computer crashed, no longer boots

[cchadwick]

(My apologies if this is not the proper location for this question)

I have a system that I built in 2012 that has been running solidly until tonight. While doing ordinary tasks, I suddenly had the screen fritz on me, before turning entirely grey (there was still some lighting, which disappeared when I unplugged the monitor or disconnected it from the computer. After turning the computer off and then back on again, the system starts up (system and GPU fans start up, and lights on the motherboard come on), but there is nothing displayed on the monitor. After about 20-30s, the computer shuts itself down before attempting to reboot (over and over).

Is it a fair assumption that the issue here is the GPU? The GPU fan seems to be working properly and it was not warm when I opened up the case, but beyond that, I have no real way to troubleshoot it by swapping components with another system.

System:
Motherboard: Gigabyte GA-Z68XP-UD3 LGA Z68
CPU: Intel i5-2500K Sandy Bridge Quad-Core 3.3GhZ LGA 1155
Memory: G.SKILL Ripjaw 4 x 4 GB DDR3 1600
GPU: Sapphire Vapor-X HD 5770 1 GB 128-bit (purchased in 2010)
Hard Drive: Samsung Spinpoint F3 500GB 7200 RPM (purchased in 2010)
Power Supply: Corsair 750 TX (purchased in 2010)

 

[popatim]

That CPU has built in graphics so you can shutdown the pc and remove the GPU., connect the display to the motherboard's ports and boot back up to see if the issue is still happening. I suspect it will

 

[cchadwick]

I considered that, but the motherboard surprisingly does not have any video ports to connect to (https://www.newegg.com/p/N82E16813128512). However, I did pull out the card this morning and while I obviously can't see what the screen output is, the computer starts up and continues running, making me think it's at least semi-stable once the GPU is out of the picture. Is it worth getting a replacement card (something inexpensive like a GT710 or GT1030) and seeing if it boots up properly?