I've discovered the best and most secure method for booting multiple OSs on one machine. Use PowerQuest's PartitionMagic to create as many as four primary partitions on each physical disk. Then, hide all partitions but the first. Reboot, and the active partition will be the C drive. Install the OS of your preference. Reboot using PartitionMagic, hide the first partition, and make the second partition active. Reboot, and the active partition is now the C drive. Install the next OS. Follow the same process on the third and fourth partitions. You can even install multiple OSs on some partitions. When you're finished installing OSs, install the BootMagic utility included with PartitionMagic. When you reboot, the system will present you with a menu of OSs. BootMagic dynamically hides or makes available the necessary partitions. In addition to clean installations, the benefit of this multiboot installation process is that malicious users can't boot to Winternals Software's NTFDOS, for example, and bypass NTFS security to pull data from the Windows NT Server installation. (The partition is hidden, so the malicious user can't access it.) Using this technique, I've built a system that boots Windows 2000, NT Server, NT Workstation, Windows 9x, Windows 3.x, DOS 6.2, and Linux.