Hey.
I am trying to defrag my C: drive. I open up the disk defragmenter and try to defrag C:. I get a warning that says: The disk defrag prog has to have 15% free space to run. I only have 3% free. Says I need to erase some files on my hard drive for the prog to have enough free space to run... That's the problem- I am not sure about how to erase from my hard drive. Help Please

Download this, it's a tril version but the only limitation in this trail version is a nag screen(no big deal) it may not give you the % you need to defreag but this app will get rid of o lot of useless files. When you run it just don't check the first 2 boxes

CleanDisk 7.6.7
Download Clean Disk Security 7.72 Free Trial - A secure file deletion and comprehensive clean-up for tightest security. - Softpedia

Have you gone in to control panel and add/remove programs and unistall programs you really don't need, this could free up a lot of free space

Uninstall programs that you don't need, burn music, movies pics etc onto DVDs ets, run a diskcleanup(get rid of temp files, recycle bin files, older restore points) and you should be able to get some space free. You can also get an external drive and move some stuff off to it. If that doesn't work, check out some third party tools which may complete the task with much lesser free space.