I had a computer running Windows Vista die recently—hardware failure (the hard drive was toast). Fortunately I had a Complete PC backup on a removable USB drive. So I plugged my USB drive into a new system that had no OS installed, popped my Vista DVD into the DVD drive, booted the system, selected Repair Your Computer from the install screen, clicked Next in the System Recovery Options dialog, and selected Windows Complete PC Restore to launch the restore process. Then I got an error 0x80070490, yikes! What's wrong?
Some playing around and I found the solution: I unplugged my USB drive from the new system, inserted my Vista DVD, booted the system, and THEN plugged in my USB drive and continued with the restore process, which worked this time.
What happened the first time? The BIOS found the USB drive during the startup process and this caused Complete PC Restore to get confused and fail.
If you have feedback concerning this tip, I'd love to hear from you.