zachman1094 0 Light Poster

Hello everyone, how's it going?
I'm trying to partition a hard drive of a desktop computer so that I can install the Windows 7 Beta on it, but I'm having some issues. I'm using Easeus Partition Manager 3.0 Home Edition to partition my hard drive, but whenever I go to change the size of the unallocated space on my hard drive, I get a popup that says "Locking Volume C!" After that, when I restart my computer to complete the changes, the computer boots fine, a screen with some writing on it flashes on quickly, then is replaced by a screen that says "This operation has been aborted", then my computer boots normally, with no extra partition.
Why might this be?
If anyone could be of any help, that would be great!!!