Reinstalling OS - Upgrade RAM - HD Get Back

I was asked to see if I could get a Dell Dimension 2400 (G6GLP41) working. When I received it, it would come up to the desktop but that took about 15 min. Only recycle bin showing. No drivers etc.It appears someone had already tried to reinstall the OS with the Dell reinstallation CD which came with it.So,I attempted to do the same thing again, deleting the active partitions and letting the CD reformat, repartition etc. All went well until files began loading back on the hard drive. It would get 10% then stall on a particular file, continue after 20 minutes loading maybe another few %. Like that, maybe getting 36% over the next couple hours. So, I replaced RAM actually increasing to 1G, and then replaced the HD.Same thing's happening Oh, and there were two Reinstallation CDs with the PC.Identical.I used them both.Each time the installation stalled, it happened on the same files.The RAM I don't mind upgrading to, the HD maybe the store will take back.