second HDD, how to delete??

Hello, i'm new here in this forum!
I'm working with Parallels 3 for Mac Desktop since January 2008.
Well, here is my Problem:

Once i've put Parallels 3 on my iMac Alu and installed a Windows XP prof. Software, a few days later, the 30GB File, i've spend to this runs full! I dont know, what is happen and why. So, i create a second 30GB File, cause Parallels wont work anymore. In the while, i called my IT Man for the Windows Problem and he fixed it.
Since then, i do not need anymore the second 39GB File on my HDD and i'd like to delete it. But: Parallels doesnt show me how! Since, i'm looking to the files, i can see two HDD, (one for the installed system and the other one), but i cant see, which is my mainsystem and what is the "empty" one!

So, i want to delete the "empty" HDD, but how? i have no idea, to do this AND to find the "empty" one....

Can you help me please??

iMac G5 Alu 24' 2,4GHZ
Parallels 3 for Mac Desktop (German) Build 5584

Thanks
Alexander

 

open configuration editor http://kb.parallels.com/en/5164 and delete hard disk 2