Clean the dust out of your computer
Today I had a graphics card meltdown. I started seeing black rectangles on my screen so powered down the PC which was locked up by pressing and holding the power button.
On opening up the case of the PC, I noticed that the graphics card felt very hot, so I removed it and took off the plastic cover over the heat sink. A few small + screws.
Then I noticed a wall of thick dust over the intake to the heat sink next to the fan. This was obviously blocking air flow to cool the GPU of the graphics card. So I cleaned out all of the dust with a brush and air duster can.
But when I re-fitted the graphics card it was dead. I tried re-seating it plus numerous re-boots, but to no avail. I guess that the GPU had melted?
In the end I fitted another graphics card to get my PC working again.
So be warned, regularly clean the inside of your computer box to flush out the dust. An air duster can is an easy option to blow out dust.
For a quick check, you could put your hand near the outlet vent of the video card to detect air flow. If there is none, then reach for that air duster.
Be careful of static when handling electronic boards, touch a radiator to discharge yourself and don't place the components on plastic surfaces. Hold them by the mounting bracket and direct the air blast only at the heat sink and fan blades to avoid static caused by the wind. I also avoid using a vacuum cleaner since it can generate static electricity. I know, I killed an electronic scale by vacuuming it!