When I try to defrag my C drive, a message appears telling me that there's not enough free memory to run the defragmenter, and to close some programs and try again. However I have no other programs running that I can close ( I have already taken off my virus checker). Is it impossible to defrag my drive?
You need to free up some memory.
Delete any temporary files, especially those in C:\windows\temp.
Delete any temporary internet files(let me know if you don't know how to do this)
Get rid of anything else you don't want and empty the recycle bin.
Reboot the computer.
Click control-alt-delete and "end task" of anything in the list except explorer. This will make sure that nothing else is running.
Try again to defragment.
Let me know if it works or not.
Actually you can check I'm on the right track by having a look to see how much space you've got left on your hard drives. I'm guessing they're pretty full. You should try to keep a couple of hundred megabytes free for the computer to run efficiently. This might mean uninstalling some programs. If you've got loads of free gigabytes on your hard drive, I'm barking up the wrong tree.