I just got a new computer and the HDD that came with it is a 320GB SATA, I've got an older 200GB 40 pin that I'd like to use as a slave or at least transfer some files from. Every time I turn on the computer with both connected it boots from the older one and Vista won't let me get start because it detects a different motherboard. I've tried every possible combination of jumpers and cable selections and the BIOS doesn't seem to offer much help, is there anything else I can do? Thanks in advance.

ye in your bios you have the option to set to boot from a specific drive... just change the setting there

What Fishy said. Just change boot priority to your SATA drive.

You might also have to edit the master boot record if the BIOS suggestions don't work. You can do this by using the recovery console.

Otherwise, just do a repair installation of Vista on the old motherboard. This will update the OS with the required drivers for the new hardware.