When I turn on CPU lights turns on like normal but no signal goes to the screen.There's nothing wrong with the HDMI cable or the monitor because it works with my Lap Top.So the CPU remains like that I can't even turn it off by holding the power button or restart button unless I cut the power . But when I leave the PC without trying to turn it on for like 3 or 4 days suddenly it works but after few busy hours again screen goes off and CPU remains like normal.Monitor is taking signal because it's not saying 'No Signal' ,Friend of mine told it could be the ram need to be replaced.Is it the RAM cause this problem? this kinda look like the error we get when the RAM is not plugged properly but here I made sure it is well plugged .This PC is nearly 2 two years old.I haven't replaced any part until today.so it's stock parts.It wasn't even slow and trouble when this problem came up,I maintained it well and it worked well.Please somebody give advise .Thank you.