Disk Utility stuck on.....

I am using a WD 500gb external hard drive (usb) and it is not showing up in Finder. Sometimes it disappears, and other times it's there and it works fine. Right now it has currently been missing for a couple hours. I ran disk utility, selected the drive, and clicked repair disk....it said all the stuff, then said "Updating boot support partitions for the volume as required." and says "7 minutes" but has been stuck there for hours!

Please help me, i am doing a football highlight video, and i need to have the file on the drive by tonight.

I'm using a macbook w/snow leopard

Okay, now i just quit disk utility,(while it was still stuck) and i unplugged it, replugged it, and it came up in finder?

Which WD drive is this that you are trying to use? Specifically is it one of the drives that draws power by connecting to two USB ports simultaneously?