I also discovered that while my Vista HDD was now ok...Win XP wouldn't boot on its hdd.
Solution...disconnect completely the vista install on its sata drive...and then install XP alone on its own drive. Now..although somewhat clunky..I have both on its own respective drive but do have to access the bios to command boot preference.
I don't need to access XP very often so this is ok until I get Win 7 .
Side note..can access specific files from XP from Vista via Win explorer.
With the sequence you outline, you have come to the easiest practical solution. You have two Windows OS's installed on different drives, with both drives connected inside the machine. To determine which you boot and use, you must enter BIOS Setup and specify the boot drive to use. Changing requires a reboot with the same BIOS change sequence.
It is possible to Dual-boot different Windows OS's, but ONLY if they are installed in the sequence (older Windows first), then (newer Windows second). When done this way, the newer Windows also will create the files and start-up menus necessary for you to choose your OS from a screen menu as you boot. But your sequence was reversed, so XP Install could not create a way to dual-boot with the LATER Windows as the other option.
I'm glad I found this thread. I hope Paperdoc will enlighten me a little bit more.
I am actually installing Windows 7 AFTER Windows Vista. BUT I still want to use the "trick" of disconnecting the Vista Drive, installing Windows 7 on different Drive, and then using Boot Sequence in BIOS to determine what OS to load.
So then, whether I'm booted on Vista or Seven, I want the Drive with the OS to be "C". I think I can manage this in "Disk Manager". On Vista I want to go and mark everything on "D" Read Only. Similary, on Seven I want to do likewise. Since Drive Letter assignments are stored with the OS, I'm thinking this is a safe way to prevent an User who has booted in either OS, from accidently damaging the other OS install by deleting/moving files around.
Fact of the matter is, the Drive on which I plan to install Seven is an IDE with 160GB. I plan to partition so that half of it is used by Seven. Then in both OS I will have Drive letter "X" for the other half so I can share files between the two OSs.