Take the old dos hd out of your 486, and put it in the xp machine. Make it the master (hdd0). Make the big xp hd the slave (hdd1). Set bios to boot to hdd1. On those rare occurrences where you want to run a dos program, enter bios, and boot to hdd0. No software tricks, no risk, totally simple. Dave Hachadorian, K6LL Yuma, AZ