Hmm, it is true that it might be something to do with the graphics card overheating (when it comes to the games),
though for it to print, it seems this will more likely be a driver issue for your printer.
What printer do you have?
and yes, graphics cards on PC's are interchangable as long as you have the right socket (most PC's use AGP as the graphics port nowadays, but some people still do use the older PCI, and the new format is PCI-E for video cards) and so, yes it probably is possible to do so, though this won't help with the printing.
Is there a fan on the graphics card? Any cards or anything blocking the vents for it? if cards are, try moving them down some PCI slots to give the AGP slot (or the graphics card slot) more room to breathe!
I hope I can help, and welcome to the forums