Does it have DOS installed? Which version? What are you doing with the files that you download?
Probably the best thing to do is format a floppy on the old machine. Put the game on the floppy, then play the game from the floppy.
While I have no idea the specs of this machine, here's a few that I played back when I only had a computer that sucked:
Star Control - A personal favorate. Fits on a floppy and even runs in CGA mode if needed.
Prince of Persia - Not sure if it'll work, but a defonate classic. If you can run this then the flood gates are open.
Metal Mutant - I think it only runs in CGA mode, but looks so good you'd hardly notice. A tough puzzler but alot of fun.
Death Sword - Two player head rolling action!
The Amazing Spiderman - It sucks so good. Hard to control and difficult, but endless hours of fun none-the-less. Unless this is a different version that I used it should have down to CGA support.
Does anyone have any RPGs to suggest? Don't the
older Krynn games agree very well with old systems? What else? If
Immortal works you're in for a real treat.