Sony PCG-R505GCK - Manual (Page 143)

DVgate Application Notes
149
To defragment a partition
1 Back up all files you want to save.
2 From the Start menu on the Windows® taskbar, point to Programs,
Accessories, System Tools, and then click Disk Defragmenter. The Disk
Defragmenter dialog box appears.
3 Select the drive you want to defragment from the list, and click Defragment.
See the Windows® operating system Help guide for more information on
defragmenting.