I'm a newbie, looking to purchase a used PC so I can start to learn Linux. I have already purchased "Discovering Mandrakelinux 10.0". It is my understanding that a used Dell or IBM is a good bet, and that everything should work. I am hoping that if I gave the forum a list of my options, someone might know if any are particularly good or something that I should stay away from.

- Dell OptiPlex GX1 P3-450MHz Desktop 128 Ram 6.4 Gb Hard (it's only $10)
- Dell G110 128RAM 6GB HD CD Desktop
- DELL Optiplex GX200, 1Ghz,128 RDRAM
- DELL Precision 530,2x1.50GHZ,512MB,40GB
- IBM NetVista P3 1GHz 15GB, 256MB RAM Computer System NR ($70)

If you have a fast modern computer with a cdrom at your disposal, but it has MsWindows on it, not to be disturbed on the harddisk, get the Knoppix cdrom. It boots, finds its way through the harware, and gives you a good feeling for Linux. Will be not as quick as MsWindows, as everything has to come from cdrom, but the speed will not be less then the old computers you mention.
www.knoppix.net

Each of the used PC is good, the more RAM the better, second is: more hardisk-space is better. If the PC has a cdrom, Knoppix will work too of course. The easiest way to install a distro is mostly via a cdrom, so a cdrom-drive is to advice.
You can try Mandrake (the GX1 has too small a harddisk I think for that), but Slackware (or Debian) will do far better on old hardware, but are more a challenge to install for a newbie, however, (certain after some knoppix experience) it is doable.

One remark: on brand-less PC's (is that correct English?) it often easy to put in some extra devices (extra RAM or extra hard-disk or CDRom or burner), they all share a common design. I am told that Dell (and IBM too) make this very difficult by their particular design. If you will not adapt your computer, and let it as is, the proposed computers sound well.

One final remark: I own a Lifetec 500MHz PIII (with Win98 & Slackware Linux). Works OK. But the PIII is a slot-1 device and the cooler makes an awful noise, a silent Pabst fan did not help. These things are going to sit loose in their slot and make then lots of extra noise. Avoid a computer with a slot-1 PIII. (Slot 1 = vertical mounted processor on a card (+ the cooler!!) like a PCI card e.g.) .