Cannot defragment D: as .....

[Sunulos]

chkdsk is scheduled to run, please run chkdsk /f.

When i do tht it says ntfs drive cannot be locked, would you like to do it next time comp starts?, i click yes, it scans on reboot, but then i get same problem, chkdsk is scheduled to run, please run chkdsk /f, and again it wants me to reboot.
I've done several full chkdsks and no probs have been found, but i really need to defragment. I've also checked in scheduled tasks and its empty. How do i get around this??

 

[KSoD]

Have you right clicked on the drive you want to check and went under the properties selection. From there you want the Tools tab. Select chkdsk and see if that will run it for you.

 

[Sunulos]

No that, like in command prompt asks if i want to do it on next restart, everytime i restart and do it, it says it again :S