Vista Tutorial - Format a disk

I just recieved a new PC.
Have 1 disk 250mb
Have 2 others 500mb in raid 1

Running Vista64.

Problem: The PC-shop guys installed Vista on the 500mb disk(s).
Didn't want that so reinstalled on the 250mb one.

Vista thinks that I have now a dual boot config. Correct.
I try to format the 500mb disk(s) but Vista won't allow me.
Says it has no access.

How can I gain control of my disks?
Alfred

What you should have done was used Acronis TrueImage Home to clone the 500GB drive over onto the 250GB drive. (Backup software for data backup and disaster recovery in Windows and Linux - Acronis)

As it stands, the only easy way to resolve this issue would be to backup your important data, then boot from your Vista DVD, format BOTH drives, and then install to the 250GB drive, as planned.

You might have been able to use BCDEDIT to "remove" the entry for the Vista installation on the 500GB drive, but that won't work in this case, because the boot sector is on the 500GB drive. You can remove the boot entry for that install, and then try to format the drive, but then you'll wipe out the boot information for the 250GB installation also.