How can I re-install Windows?

ROU_Xenophobe, getting somewhere, thanks!... Yes I do have a CD drive and different DVD drive. I attached the cable going into the CD drive into the DVD drive and was able to start the setup. But... I've now got a blue screen saying "Windows XP Professional Setup" and at the bottom it says "Examining 76294 MB Disk 0 at Id 0 on bus 0 on iastor..." and it's been like that for 25 mins with no change. Is it actually doing something or is it hung up? I really don't trust this thing. Is this "Examining..." phase something that could take a while?

Simplify and do what the system "wants" until you get back in control of it. That means for starters, un-reverse those cables and do a clean install from Windows CD, not a DVD, the way that your default system "expects". I am sure you have or can burn a Windows SameVersion installer CD, perhaps using your Mac to do so, and since you're going to use your own legit serial number on installation anyway, the particular disk/image you start with doesn't much matter, imho. For that matter, once it's up and running you could even reinstall from "your" DVD a second time to be extra-normal. I'm on my Macbook Pro right now, and about to throw the Dell off my 10th floor balcony. That'll also work. Take pictures.

I'm not even sure if I want to install another (third) hard drive. OT1H, a new hard drive would be cheap, like $40. OTOH, installing a new hard drive is a bit of a pain in the ass in that model, if it's the one I had. OTGH, *if* you can afford it it would be much more cost-effective to just build a new machine rather than keep that one stumbling along.

Many Dell's have a hidden recovery partition that can be used to reset the computer back to the factory default image. No disc is required to do this. You normally just need to hit a hey sequence on boot up Try: When the Dell splash screen appears during the computer startup process, press and hold and then press . Then, release both keys at the same time. For more information see: http://support.dell.com/support/topics/global.aspx/support/dsn/en/document?journalid=6F99F89A81F83C82E040AE0AB8E13A5B&docid=336966

I was getting the same error message on one of my PCs. It turned out to be a bad stick of memory. I'm not saying this isn't an OS issue, but you might want to try a http://www.memtest.org/.

Delmoi: See above - I have separate CD and DVD drives. I had to reverse the cables to get it to boot from the DVD.

I can't start windows in safe mode. I get a screen full of errors such as: multi(0)disk(0)rdisk(0)partition(1)\WINDOWS\system32\DRIVERS\xxxxxx.sys and so on... Those aren't errors, they are regular messages telling you that a certain driver has loaded. If you're turning the machine off after seeing those, rather then waiting, you might not be giving it a chance to finish booting. Also, normally when a bios says "Boot from CD" that usually includes booting from the DVD, after all, when you boot from a DVD you're using the same drive as you would be when you're booting from a CD-ROM right? On most machines, you should be able to boot from a DVD by selecting the CD-ROM option. You should at least try it.

Conrad, I think you might be right. Especially after finding http://www.gamespot.com/pages/forums/show_msgs.php?topic_id=26818707 (See the third post, same thing happened to me). I'm not even sure if I want to install another (third) hard drive. Who knows how long that would last until it fails also. There must be some other underlying problem, and I don't have the will left to deal with it. Over the balcony it goes. Thanks everyone.

Sounds like your hard drive might be totally cheesed - or perhaps there's some problem with the connectors. I recommend creating an http://www.howtogeek.com/howto/windows-vista/use-ubuntu-live-cd-to-backup-files-from-your-dead-windows-computer/, which will let you boot up into Ubuntu OS (very easy to use) entirely from the CD drive. Once the OS boots, you'll be able to determine if you can see your hard drive at all, and hopefully access the files on it. This won't be dispositive, though - it won't tell you if your hard drive is dead, or if a cable or connector is cheesed, or what. For that, you might need something like Spinrite.