I own a Compaq 4840 which is a P2-266mhz * 320mb of ram. It use to have a slow 6GB 4200RPM or so HD but I replaced it with a 80GB western digital 7200rpm ATA/100. After doing so I cannot install windows XP on it. It will boot the setup and run the format and setup copy but once it restarts the screen goes past POST and just goes blank. If I install XP on the HD from another machine and try to boot it, samething will happen. I am guessing it can't boot Windows XP for some reason. Installing almost any Linux distro works perfectly fine. So it is not a size limitation. Installing XP on the old 6GB HD works fine also.