These steps will put a more permanent fix to the problem:
[Before doing the following (or any serious disk mod's really) you should back up all data to alternate media; and satisfactory results will depend on whether or not you've been doing "check disk" concurrently with your other weekly Windows maintenance chores.
If you haven't, then there could be corrupt sectors, which will adversely affect data copy and read-back. Do that after data backup.]
For some immediate 'c' disk space gain, delete all but the most recent Java version & update from 'Add or Remove Programs' (see 'Control Panel'> Add or Remove...);
Also, delete old 'Restore Points' (if your system is behaving itself) like this:
Make a new Restore Pt.; then go to System Tools> Disk cleanup> (after it's done examining the disk)> More Options> System Restore button @ bottom> Clean up> Yes.
One disk space reclamation item is to 'compress contents' and 'allow index service'. These help optimize file recovery speed & save disk space.
Start> my computer> right click 'c' drive> properties> general tab: here check both boxes & 'OK'.
Don't freak out: it may say hours (or days) to run, but this drops dramatically as the process advances. Just walk away and let 'er run for the duration: it will self close when done.
Depending on the files & sizes, it may take several hours to do (maybe do it at night @ bedtime?).
Download "CCleaner" http://www.piriform.com/ccleaner
Freeware.
Run the various tab headings, but especially "Windows" and "Registry" cleanup. Backup these initial files when asked to: they may be needed if things don't go right.
Defragment (although this will not increase 'space available'). Freeware: "Smart Defrag 2"; http://www.iobit.com/iobitsmartdefrag.php