I assume you're now selecting boot drive from MB BIOS or a proprietary boot manager, and whichever boot drive you select comes up as C: If your XP drive is FAT32, and not NTFS, you can do what you want but it will be a little work. First, you've got to copy your win9x boot files (io.sys, msdos.sys, command.com) to the XP drive, and edit msdos.sys Paths section to point to D: instead of C: - then you've got to create a bootsect.dos file - a file copy of the win9x drive's boot sector, which ntldr uses to boot the win9x drive. Easiest way to do this would be to copy it from another dual-boot machine. Else, you've got to run SYS c: after booting with a DOS floppy (abd then replacing the DOS msdos.sys with your win9x one, which will have been overwritten), or running SYS D: from within win9x (assuming your XP drive shows up as D: in win9x). Running DOS or win9x SYS to your XP drive will, of course, destroy your XP boot, which will then have to be repaired using an XP repair install or by running fixboot from Recovery Console. With win9x then coming up as D:, instead of the C: it was installed on, you'll have to change all your shortcuts, etc. All in all, it might be better to leave things as they are. Some day, if ever you have to frehly reinstall your operating systems, put win9x on C:, and then XP on D: - then the boot will automatically be set up for you.