Remove the hard disk from the 98 PC and put it in your other PC as a slave. You can then read and copy files off it directly. Installing a second disk here:
http://www.pcanswers.co.uk/tutorials...ectio nid=606
If you don't fancy doing that, buy an external 3.5-inch enclosure for it (2.5-inch enclosure if it's for a laptop disk), fit disk inside the enclosure and plug it into a USB port on your other PC.