System Keeps Starting and Stoping

[Yoshi with a Gun]

I have a system that I can't seem to figure out. It seems to keep posting, then turning off, and on, and off, and on. I'll see the HP logo appear for a second or so, then a "VGA No Signal", then the HP logo. This loops indefinitely. From my understanding this started after a recent windows update. I've tried a hard drive component test, as well as a memory through the HP diagnostics. Currently wrapping up a full system extensive test. Will update when I get the results. I have reseated the RAM, changed monitors/ cables, and tried launching windows from different drive. The issue persists. The screen stays up while in BIOs/Diagnostics. Any idea of what the issue could be? Tech support so far has been about as helpful as ever.

 

Update: As expected the system extensive test came back without issue. Says everything passed.

[emosun]

can you pull the drive out and see if it will stay running in legacy bios mode

[Yoshi with a Gun]

13 hours ago, emosun said:

can you pull the drive out and see if it will stay running in legacy bios mode

Not at the moment. To get the drive out I have to take the heat sync off, and I don't have any thermal paste atm. I don't believe that the issue however. When I tried to boot windows from a flash drive I got the same problem.

[emosun]

Well youll basically need to start removing hardware until the machine can sustain its own power to narrow down the faulty component