I have tried many times (unsuccessfully) to defrag my hard drive. Every time I do try and run defrag or cleanup I get the same message saying that I haven't enough free space. I have deleted everything I can, rebooted, closed down all running programs and I still can't use either. Is there a fault or am I destined never to use these tools?
The only thing i can suggest is to try starting your computer in safe mode. From when you turn the computer on, keep pressing F8 loads until you get a screen come up asking if you want to start in safe mode. Do this, and it should work. All you need to do at the end is reboot, and it should start back up in normal mode.