How Do I Make An Old 2000 Computer Faster?

You can check the hardware (motherboard, video card and sound card are the most important) from those win7/Vista Desktops at best buy and double check for hardware compatibility with windows XP drivers then just buy a windows XP Professional, you can search at sites like amazon.com, nextag.com, ebay, etc. Just be aware that your windows XP 32bits will only "see" 3Gb ram in case the Desktop you looking has 4Gb+ memory. Unfortunately is not easy to find a good desktop with windows XP it is officially out of market. I built my PC from scratch: mother board for ddr3 memory , got 6Gb ram but at windows XP only 3gb is working the whole memory is ok at my win7 64bits and Debian Lenny 64bits, video card is old but still good GTS250.

Good luck, Terry.