The computer that became unusable with XP had 16mB video RAM, 512 MB PC2100 DDR SDRAM memory, and used an Athlon XP2000+ processor (speed 1666 MHz, bus speed 266 MHz, and CPU cache 256K). It used to work acceptably, but over time got to where it did not. I tried to disable extra toolbars, etc. that tend to get downloaded over time, and eventually disabled the antivirus. I am not sure why it did not work, as the memory checked ok. Maybe it needed a defrag. Anyway, rather than troubleshoot it further, I chose to install Linux, and it is now useable. Probably if I had reformated the hard drive and reinstalled XP it would have been useable again, too. Admittedly, I have not had the Linux long, so it might bog down over time. I have had other XP computers, and their performance always seems to get worse over time. Part of this is that newer programs are designed to use more memory, so the operating system used to work well with older programs, but not as well with newer programs.