Hi Michel,

Does the video card have a fan on the GPU?  If so, cleaning the blades and cooling fins of dust might help.  I had a video card in an old PC several years ago that was so clogged with dust that the fan wouldn’t even rotate.  Even after removing the dust, the fan still wouldn’t turn, and I had to replace the fan.  You might want to pull the video card out, blow all the dust out, wipe the blade contacts with isopropyl alcohol, and insert+remove the card into the slot a few times to exercise the contacts.

While you are at it, it might be worth blowing the dust out of the power supply as well.  Every 6 to 8 months I open the PC case, and use a vacuum cleaner with the hose connected to the exhaust, and blow all the dust out of the case, off the CPU, off the GPU, off the various cooling fans, out of the power supply, etc.  It is surprising how much dust creeps in when running the PC 24/7.

Good Luck.

Ken