i would try 1 ram at a time,run a test for a few hours,then another sitck for a few hours.but from what you have said yes it sound like you have some bad ram.

if u do find a bad stick it would be your best bet to replace them all because in order to get the max out of your ram you must run a match set (all the same kind/speed)that is why they sell them in kits.

this is a link just in case 

http://www.howstuffworks.com/ram.htm

hope this helps

Yes, Memtest showing errors should be all you need to diagnose a bad RAM stick.  In theory replacing the RAM in sets is best, but if money is an issue, replacing just the bad stick should work fine, in actual use I doubt you could detect a difference.

Thanks to both.  I will try the individual ram stick tests today.

would this be causing the problems while trying to re-install XP?

I wouldn't want to say absolutely without seeing it, but yes, a bad RAM stick can certainly bugger an install.

That was it!  I found one 1G RAM chip that was bad.  When attempting a clean XP Pro install after removing the bad ram, everything installed flawlessly.

Thanks for all the help!

Any suggestions on where to look for help with setting the old hard drive (80gb ide) as a slave so I can retrieve my data?  (I replaced that drive with a new 160gb per Dell's instruction as they said I had a bad hd.  Probably not true, I just had bad RAM?)

Congratulations!

To set up a drive to retrieve data, you can hook it up via USB using a kit like this: http://www.newegg.com/Product/Product.aspx?Item=N82E16812232002

http://www.wikihow.com/Add-an-Extra-Hard-Drive

or this 1

http://www.dtidata.com/resourcecenter/2007/04/23/how-to-slave-hard-drive/

sorry i never messed with ide so this is the best i could do.

if this dont work just google "how to hook up an ide drive as a slave drive" or something like that.