Intermittent Boot Failure – Black Screen & Loud Fans on Startup

For the past few weeks, my desktop has been unreliable when powering on. Sometimes it starts normally, but more often the fans spin up loudly, the screen stays black, and nothing happens. A few rare times it will reach Windows only to crash or blue screen shortly after.

Once it’s running, performance in games and temps are perfectly fine, so this only happens during startup. I’ve tried reseating RAM and cables, updating drivers, and clearing CMOS, but the problem keeps returning.

Could this be an early sign of GPU failure, power supply issues, or something else? Any suggestions would help before I start replacing parts.