Minimum Hardware Requirements

You could run it on one of those old machines, just make sure the CPU is more than 500Mhz PIII class, RAM, minimum 256mb, 512mb better and you could add a PCI SATA card (pretty cheap these days) to use for storage, but knowing the crap cases that Compaq and HP use, room for hard drives is limited, the power supplies are junk and the motherboards from that time are really badly prone to having bad capacitors...

After some testing, I ditched the Compaq one because it didn't work (I saved the Celeron CPU and the RAM). Now I'm thinking of using an Everex from 2008. It has 1 GB of RAM and 2 SATA ports (more PATA ports, but that pc is flaky with PATA and SATA at the same time). It's CPU is pretty slow (don't know how many GHz, I can find out). If the celeron is good enough, and is compatible, I might use that CPU.