Cant shrink drive more than 73 MB HELP!

I have a 240 Gb internal drive in my laptop with about 100 gigs left in it, I want to bite off a 30 Gb chunk so that I can install linux on that partition. Unfortunatly i can't shrink the drive more than 73 Mb. I turned the pagefile and snapshots thing totally OFF but it didnt do anything, still only 73 mb. I also tried defragmenting the drive with the built in one and with a 3rd party defragmentor. That still didnt do anything either. I'm out of ideas.
Anyone know any other ways that I can increase the shrinkable space?

There is a solution in this thread, look for a post by "julzx94"
http://www.vistax64.com/vista-general/41431-disk-manager-not-allowing-me-shrink-partition-2.html
I haven't tried this and hope this will atleast give you an idea to solve your problem.