Computer Monitor Loses Signal?

This kind of question probably belongs on a dedicated tech support forum; but I have a desktop computer I've used for gaming for a couple years (I got it on craigslist for a good deal). The computer is an HP Pavillion HPE. I mostly used it for less intensive games (Minecraft, Undertale) but I've played some more intensive simulation stuff (Children of a Dead Earth, KSP, Space Engineers).

I think I first encountered this problem while running KSP; the monitor would lost connection and went to sleep, though the computer would continue to run. I checked the monitor connection, tried using a different monitor and cable, and it made no difference. I tried updating my graphics driver to see if it would help run some of the more intensive games. I even tried moving the computer next to an AC vent in case overheating was the problem. The problem persisted; 10-15 mins after running any game (even vanilla minecraft) the computer loses connection to the monitor.

The computer ran fine on these more intensive games for months. The problem arose the first time I moved the computer up to my room. So far as I know everything is connected correctly, and the computer was not mishandled during the move.

Do you have another computer that you can test the monitor on, or another monitor you can test the computer on? I would suggest trying that so you can narrow it down to one or the other (or neither, if it's a problem with the cable you're connecting with.

Also, you said you moved it closer to an AC vent, but it might be worth opening your desktop and cleaning out any dust inside - that can easily cause it to overheat if you haven't cleaned it in a while.

I also found this HP forum post (also for an HP Pavillion) that suggests going through your BIOS and resetting your video settings. It's possible that a Windows Update may have messed up something with what port of the graphics card it works with, so you might need to reset the video settings in the BIOS to that.

It's possible that it may be faulty capacitors on the power supply board. I've had various newer LCD and LED monitors with bad capacitors. They will usually work for a while, then shut off or go blank without warning. Not very expensive to replace if you can solder them, or know someone who can do them for you.

http://www.xjimx.com/dreamviews/Misc/BadCapacitors1.jpg
Capacitors with slightly swollen tops.

You said that you experienced that problems when you moved your computer into your room. If all your drivers are updated then, possibly it is temperature problem. Make sure that you cpu back is clear. Hot air flows out in the back of your computer case. So, if your computer back has debris. It can block the hot air that flow out from your cpu.

That was it. Turns out the person I bought this rig from never cleaned it and the inside was full of dust.