Virtual HD too Large - How to shrink?

I don't use parallels all that much and with HD space shrinking, I was hoping to find a way to reduce the file size of the virtual disk. I currently have Windows 7 installed on Parallels 5. The disk size is 25GB, I'd like it down to about 15. I've tried compacting but that hasn't done much. Do I need to delete the virtual disk and reinstall windows? Honestly, it wouldn't be a problem, I don't have anything critical installed, but if I could avoid the hassle, that would be great.

 

Just clean install of Windows 7 with paging files and hibernation could be about 10 GB.

You could use some tips to free space. Like this http://www.addictivetips.com/windows-tips/6-ways-to-free-disk-space-in-windows-7/
And then use compacting to get advantage of your actions.

Reinstalling windows always helps, but it is like using a sledge-hammer to crack nuts.

 

Thanks. I will give that a try. I haven't installed much on it and don't have many files stored there, so I'll be interested to see what's taking up space.