2010 Mac Mini doesn't display video output.

I was using the Mac in Windows. I restarted Windows to boot back in to High Sierra, where I was followed by nothing. Nothing. No display output. No chime either, but the last time I booted into macos the sound was muted, and it doesn't seem to chime when the sound was left muted. No caps lock indicator light.

What I've tried - PRAM reset - SMC reset - Replacing RAM - Different Monitors - Safe Mode - Holding option to boot to the menu - Attempting to use the boot menu to boot windows (I can verify this hasn't worked because RDP is enabled in Windows) and too the recovery partition. - New cables (display and power) - Different keyboards. - Restarting monitors and the Mac - Unplugging power from monitors and Mac.

Just about the only thing I haven't tried is too leave it for an extended period of time.

I'm completely stumped. I haven't had the Mini long (bought it used) and all the signs seem to point to GPU failure.

When I power it on, the SuperDrive and fans spin up, the power led on the front comes on, and nothing else happens.

Does anyone know what on earth is going on here? Thank you.

Edit: Leaving it on over night seemed to do nothing. It still won't work, and I've just read through the correct section of the Apple Technician's Guide, which I found randomly on the web, and it still won't boot. Look's like I'm going to have to contact the eBay seller. Thanks all for your help.

Edit 2: Sorry for delay. Contacted eBay seller and returned it. Ended up ordering a new one, which the seller didn't have lol. I ended up buying a 2014 i5 model for not much more which I have now set up with Mojave and Windows 10. I would have installed something newer, but Monterey and Big Sur both chug on this machine, so I'll stick with Mojave, or maybe upgrade to Catalina. Still beats the first Mac Mini's High Sierra and Windows 7 requirements.