external hard drive permissions

So I've got a Vista ultimate desktop, and a ubuntu linux laptop.

I also just bought a new external hard drive, and for some reason, my ubuntu
laptop has no write permissions to it. I tried looking at its permissions on
my vista desktop, but I can't seem to add permissions for people that aren't
somehow connected to my desktop. For example, there are permissions for
administrators, users, SYSTEM, and authenticated users, but they all refer to
the vista desktop. How can I give my laptop write permissions to the hard
drive?

Or, perhaps an easier question: How do I remove all restrictions from the
hard drive?

please help!!! :-D

thanks