Couple of suggestions:
1. How full is the hard disk? Sounds like you have just a single hard drive. Try removing some stuff from it if it's pretty full.
2. When is the last time you defragged the hard drive. After you empty some stuff off it, try defragging.
3. Is DMA enabled for the hard drive. If not, enable it. That will probably be the single best thing you can do for it.
4. Try "compacting" your audio data using the "compact audio command" (I assume HS2002 has this command.)
5. Do you have any programs running in the background (virus scanner, system monitor)? If so, shut down whatever you don't absolutely require.
Some or all of the above should help.
At some point you might want to consider adding a second 7200 RPM hard drive for your audio data. But even so, you should be able to run six tracks. My DAW is a 733 MHz PIII, and I can run at least twice that complete with realtime effects. (But I also have 2 7200 RPM hdd's

)
Good luck and let us know how you make out.