Any ideas?

So. We have a number of computers in my computer repair class that are so ungodly slow, we can't install operating systems on them. The systems in question are XP or 2000, and the computers in question are Dell Optiplex Deskpro EN or summat. Designed for 98/2000 ish. Should have plenty of ability to run/install at least 2000.

My current one won't get past the full-color Windows 2000 start up screen. The little bar that's next to 'Starting Up' at the bottom doesn't move at all, and I've left it on for hours at a time. Since that install hadn't even been set up yet, I said screw it and tried to reinstall 2000. It took the CD at least 30 min to load, and another hour to format the new partition. There is something wrong here and I don't know what. I can't put any new RAM into it, because the computers are so old they only have 2 RAM slots, and all of our old crappy RAM is only like 64Mb each [ie all the ram that fits in the comps is only small amounts]. My comp has 128Mb of RAM I believe. And there's nothing I can do to fix that.

I believe I have tried installing 98 on it, but when I attempt to format the HD after fdisking it, it can never find the HD (says c: invalid media type) and I can't do anything with it past that.

Another one gets to the Windows XP setup and freezes at naming the computer/workgroup part and has to be restarted to attempt to do anything. Hard drive was replaced, and it seems to work now, as it already had 98 on it.

So any suggestions you may have on how to install OSes better so they actually work would be appreciated.