It sounds like a Harddrive in prefailure mode. If you are installing W98, you must have the W98 Boot Disk. Put it in the Drive and boot into DOS. At the A; Prompt, type and enter       scandisk C: It wil do five checks and then ask you about a surface scan, Let it run that and be patient as it takes a while. If it will not run completely through, or does run through, but shows bad sectors. get a new drive. You can also try this command which has a different approach 
scandisk/autofix C: Note that there is a space before the C:    These two commands have saved me many headaches over the years, as I still use W98SE,  and when I get a freezeup, or BSOD, I reboot and run the second command. Most of the time it will show that the free space count was fixed at the end.

Thanks for the suggestion... but I ran scandisk, it did the full surface scan, and it went all the way through and showed no errors, and that all drives were fine.  But next time, I'll keep that in mind.  Well, uh, any other suggestions?

Download the Dell Diagnostics and make the four diskettes. You can do that on another computer. The Diskettes are used in DOS also; let them check the computer and see what it finds. Just in case you might have picked up a boot sector virus, if you have a Mcafee's Antivirus CD, that CD is DOS bootable and will check for a virus before windows loads. FMI, how big and what brand is the Drive?

Sounds like it might be a (RAM) memory problem. The Dell diagnostics might detect it or you may need to try a more specialised RAM memory testing program (which you should be able to find for free on the net using Google).

Thanks for the advice... I got the Dell Diagnostics utility, and tested everything... everything seems to work fine except for the memory... it keeps on locking up as it's testing the memory. So does this mean my memory is bad?