In the comments of a recent post I did, reader Glaurung Quena brought up a good topic: secondhand PCs, acquired cheaply, strictly as rebuild fodder.

I like the idea, of course, because I’ve been doing it for years. In the 1990s I built a lot of 486s and Pentiums into former IBM PC/ATs, basically until all the board makers relocated the memory slots into a position that wasn’t clear on the original PC/AT due to a beam that supported its drive bays. And of course the adoption of ATX and MicroATX killed that, at least for a while.

But now ATX has been around as long as the old AT architecture had been when ATX came along, and efforts to replace ATX haven’t been successful. So that trick makes more sense again. Buy a secondhand machine cheaply, intending to re-use the case, and regard anything else inside that happens to be reusable strictly as a bonus.


Old PCs turn up anywhere that any other used items do: Garage sales, estate sales, thrift stores, and church rummage sales all have possibilities.

Thrift stores probably make the most sense, as they’re open six or seven days a week. Many of the chain thrift stores don’t accept PCs, but independent stores often still do.

Garage sales can make sense, especially if you’re out running errands on Saturday morning anyway. Take the long way through residential areas, and eye the selection from the street. Keep moving if all you see are clothes.

If a neighborhood near you decides to have a neighborhood sale, that’s frequently worth going to. People who don’t think they have enough to warrant having their own sales are more willing to drag their stuff out and see what happens.

Rummage and estate sales are a little trickier. You’re more likely to find them in affluent areas, because young professionals are more likely to buy them and replace them. And sometimes at an estate sale in an affluent area, I find a cache of PCs in the basement. I find it happening more and more.

The trouble with estate sales is having to go into the house and dig. You don’t have to worry about getting there early and fighting for a place in line, because the computers will still be there at noon. The people fighting for a place in line at 7am are looking for jewelry and Lionel trains. It’s hard to recommend the estate sale circuit unless there are several things you’re looking for.

The other possibility is getting them from your workplace. If your workplace is paying to have its old PCs hauled away and disposed of, they might be willing to give you or sell you a PC without the hard drive in it, as long as you’re willing to sign a release saying you accept all liability and expect no technical support.

What to look for

The big key is knowing ATX and Micro ATX when you see it. Although many name-brand PCs do adhere to industry standards now because it’s cheaper, there are some exceptions, especially small form factor PCs.

Look for the ATX backplate to be in the right position, and either 4 or 7 full-size expansion slots perpendicular to the motherboard. If they’re parallel to the motherboard, then you probably have something else.

Then again, if you’ve read this far, you probably already know that.

The other thing to look for are USB ports. In the 1990s, peripherals were so scarce you rarely saw more than a couple of ports on the back of the motherboard. Nowadays, if you don’t have at least a couple of ports on the front, it’s a pain. So much so, that in addition to the ports on the front of my computer, I keep an extension cable plugged into one of the rear ports to give myself another one up front.

What you save

A good quality case costs a minimum of $35, but can often cost closer to $100. A power supply isn’t necessarily included in that, since the customer’s needs vary so much.

If the system itself is a Pentium 4 or older, there isn’t going to be much usable stuff in it. The memory will be obsolete, and of course CPU upgrades will cost more than the machine will be worth. The question with what’s inside is whether it has resale value or recycling value.

If the power supply doesn’t have a 24-pin power connector and SATA connectors, it’s probably not worth reusing. You can buy power adapters to modernize them, but the power requirements on newer equipment can be different. You can spend $15 on adapters and maybe it will work, or you can spend $35 on a newer power supply. Also, Dell used odd power supplies with their own pinout for many years. They looked like ATX, but the wiring was different, and if you plugged a regular ATX motherboard in, you’d blow it up. So you should assume any Dell power supply will need to be replaced. The upside is that since Dell power supplies from the P1-P3 era (at least) can only be replaced with other Dell power supplies, they’re more likely to have some resale value. (I don’t know Dell PCs all that well because I’ve made a habit of avoiding them whenever possible. Booby-trapping your power supplies and knowingly using bad capacitors gets on my nerves for some reason.)

The optical drive could be reusable, depending on whether it still works and is still useful. Plain old CD readers get less and less useful by the day. With DVD burners typically selling for $20 these days, it’s not the end of the world if you have to buy one. But if you have a choice between a couple of different systems, you might as well get the one that has the best optical drive.

Floppy drives are even cheaper. But your new motherboard might not even have a connector for one of those, and even if it does, you may not use it anyway. There’s a decent chance you’ll be replacing that drive with a memory card reader, which is far more useful these days.

But in the middle of the last decade, more and more systems started coming with those built in. Since those readers cost about $15, it’s worth looking for a case that already has one. They plug into a USB header on the motherboard and most motherboards have plenty, so you shouldn’t have any problem re-using it.

Sometimes a PC will have useful cards plugged into it too. The majority of modems aren’t worth the hassle of course. A modem with a real hardware controller on it could have a little value. Network cards usually aren’t worth much hassle, but if you find a gigabit card, that can be nice to have. USB and Firewire cards are nice finds too. You can never have enough of those ports.

The hard drive is probably old, slow, and small, but if it’s not useful for anything else, a hard drive with a Windows XP installation on it is nice for those times when you have to install Windows off an upgrade CD. Plug the drive in long enough for the upgrade to notice it, then disconnect it after the installation finishes.