Actually, I was asking about the reverse; booting to the XP drive and accessing the files on the Vista drive. Would it help if I changed the Vista drive to the slave drive and set the XP drive as the master drive?
You need to look in the BIOS options and see what can be done. The BIOS may have an option to 'swap' the boot drive. On some PCs there may be th option to boot from one of five different devices. Or more.
About the files system. Both XP and Vista use the same NTFS file system. Right now I am on my XP system, but I can peak into both drives and all partitions. But some files I can not easily modify, they are protected by the other system.
So yes, put your XP system into the PC. The limitation is if the XP system was working earlier on that very same PC. If not, you may have a hard time. It has something to do with HAL. Different PCs have different HAL files.
The keyword HAL is in the CH database if you wait more info.