看你要怎麽用？？

if you want to play game, yea, go ahead. It'll make it better. TNT4 is a little old, but still should support many games.

When you say you can't play those games, what did the program say? did it say "legacy video card..." "imcompatible video card?"...or is it just slow? If it is just slow, you can go ahead and get a new card. It should make things faster, but again, your computer is pretty old itself. I suggest you buy a new one, if you need a cheap computer, I can tell you where to get one.