Increasing Hard Disc capacity on Servers

deleting un-necessary files.

back them up first if you might need them.
you can attach a network storage device to your network and configure it for use on your server.

you can add the disks inside the server if there is room. consider the extra heat they produce.

As this thread quiet for a while, I wonder if you have solved your problem. Assuming you have fixed, in case of who have the same problem. I think there is a better solution with step by step tutorial. I hope it will be helpful.

http://www.partition-magic.org/server/increase-free-disk-space-in-c-drive.html