I'm a total dweeb in many things, including AH and building computers. But I went to Mwave.com and got a barebones system (case, mb, cpu, floppy _ all assembled) threw in some ram (which they installed) and then used components from my old machine to build a computer that works really well (much to my surprise) and only cost me about half or a quarter of what it would have cost if I'd bought a complete system.
Total construction time was maybe two hours.
Toughest part was reformatting the HD and installing win98, and that was pretty easy once I checked the MS site (and I don't know, I might have been able to get away with putting my HD in and using the old windows install, but I didn't want to take the chance.)
I could probably have done it even cheaper if I'd wanted to just buy the components and do all of the building myself, but for a starter this was a cheap, easy alternative that increased my confidence for future computer projects.
Good luck.