Why does my computer keep freezing? Is it because of the PNY GeForce graphics card?

Don't know if this helps or not... Recently, my laptop was running real slow and I tried everything to fix it... defrags, registry cleaners, PC fixit software, etc. Nothing worked. Finally, I turned the laptop upside down and saw that the cooling vents were clogged with fine dust and silt. After vacuuming the vents, my laptop was back to normal.