I think I may have shot myself in the foot...

I have a set of three SATA harddrives and a DVD-Rom as the primary IDE drive (out of the box Alienware setup). Vista is installed on the first of the SATA drives. Everything works fine.

I canibalized a 200GB IDE drive from my old system and decided to install XP on that drive (for various preformance and compatability reasons - and for space reasons I did not partition my current SATA setup and install XP that way. I have done that and it works fine, but current projects leave me needing all the space I can get right now). The install goes fine and the option to boot to Vista dissapears. I use VistaBootPro and Vista comes back, but now XP goes away...? Long story short, after fiddling with VistaBootPro, I can get Vista to boot fine but get the NTLDR error when selecting XP from the boot menu. I figured out that I can get XP to boot if I leave my Vista install DVD in the DVD-Rom drive, but do not press any key and boot per normal, choosing XP from the boot list. More fiddling with VistaBootPro and I lose the ability to boot to XP at all (always the NTLDR error) and I now have to leave the Vista install DVD in to boot into Vista. Vista cannot repair the boot section using the Vista install DVD (although it thinks it does successfully). VistaBootPro says everything is fine as well.

I think the issue may be SATA vs. IDE as Vista sees the IDE drive as the E drive and the first SATA drive (where Vista is installed) as the C drive, but XP sees the IDE drive (where XP is installed) as the C drive and the SATA drive as the E drive. The boot.ini sees the IDE drive as the primary drive/partition/etc. all set as zero.

I suspect I can fix this mess by simply removing the IDE and repairing the Vista boot section, but is there a way to resolve this mess with the IDE attached and without reinstalling Vista?

Cheers.

"....Vista sees the IDE drive as the E drive and the first SATA drive (where Vista is installed) as the C drive, but XP sees the IDE drive (where XP is installed) as the C drive and the SATA drive as the E drive."

AFAIK, the above is more like the norm .... the drive letter C: is supposed to be set aside for the prevailing system drive or partition. The other thing you seem to have overlooked, is the master boot record (MBR) routine.

When you added the cannibalized IDE & decided to install XP on it, the boot record for Vista was automatically invalidated, this is because XP simply overwrote the MBR entry on the SATA, making the IDE drive at that point the prevailing system disk. To avoid this in the future, you need to ensure that you install the OS in the order of release -- old first, newer last. You can't blame XP for overwriting the existing (Vista) MBR because it is unaware of what it is & how to accommodate it.

Vista's MBR on the other hand, would have had no problem with XP had the install routine been the other way round, because the OS is aware of XP's MBR & knows how to modify its MBR to reflect XP, so both OS' can be booted from subsequently.

Have you made any progress since your original post? Are you still unable to boot from either OS'?

As I thought, I simply removed the IDE drive and ran the repair feature on the Vista install DVD and things are back to normal. I've decided to clear up some room and make a small partition on my SATA and simply install XP on there. After a quick run of VistaBootPro, both Vista and XP are happily running. I have been able to reattach the IDE drive and use it as a sotrage drive.

Thanks for the help.