System Restore has filled my HD!

Running Win ME. Although I turned off System Restore the damn thing has filled the OS partition (3Gb) of my HD (20GB). It won’t let me delete any of it as it is “in use”. Is there a way for me to force-delete the files eg-boot from floppy to minimalboot & use command line instructions? Question 2 is Why did it still fill the drive with these .cpy files when System Restore is turned off? How do I stop it from occuring again? Thanks.