So I want to put Ubuntu on a hand-me-down Macbook Pro that has been reformatted with Win7. True story. The catch is that I don't have any blank CD's left, so rather than wait till tomorrow to buy some I want to try reformatting tonight with my USB drive.

What I've found out so far is that I need to format the drive with a GUID Partition Table. diskpart is supposed to support this, but it throws "The specified disk is not convertible [...]" when I try to run the conversion. I haven't been able to find any 3rd party tools to perform the reformat yet. Any tips?

Thanks in Advance,
Sir Ducky