I am having problems defragging my PC, I have Diskeeper 10 installed and it is telling me that chkdsk needs or has been scheduled to run and defrag won't work untill it has, I have gone to run chkdsk c: /f and then typed Y when it asks if I want to run at next restart, however it doesn't run, I have tried on numerous occassions with the same result, I have ensured that windows is up to date, any ideas?