well i have been trying to run the defrag on my computer for a very long time now (talking months) and every time i do it says operation cant be done please run /chkdsk f. i go to the run app and do run /chkdsk f and it brings up a comand window and says that the volume is being used and if i want to run it next time the computer starts up. i said yes in hte past and restart only to find myself back where i started at before i rebooted. i say no and i still get the same message (not rebooting this time). What can i do?