Installing Windows Vista has proven to be more challenging than XP. It seems to fail a lot easier and gives less information on why. Here's a couple things I've run across that are issues and how to work around:

If you get an error referring to the disk being unusable due to having a GPT partition, that disk as at some point probably been in a Mac... To get rid of the GPT partition and make it usable by Vista (note that the following will destroy all data on the disk!):

1. At the disk selection screen, press Shift+F10 to get a command prompt
2. Run "diskpart"
3. "list disk" (see what's available)
4. select the current disk (example: "select disk 0")
5. "clean" (wipes out the GPT partition)
6. "exit" (to quit diskpart)
7. "exit" (second time closes the command prompt)
8.  Now you can refresh the disk selection in the GUI and continue.

If you get more generic errors having to do with the disk not being compatible, compliant, or unsupported, check to make sure that the boot order setup in the BIOS is configured in the following order:

1. Drive containing the installation media
2. The hard drive that you want Vista to install onto

If you have ANYTHING (even removeable media) configured above either of those two items, the installation will fail. Vista appears to attempt to write the boot loader onto the first writeable media in the list, even if it's a memory stick or a floppy drive! Obviously, that's a bad thing... :)

Hope these tips can help prevent the hour of frustration and googling that I had the other day!