this will force defrag even if system is low on resources
you can also use
-a Analyze only
-f Force defragmentation, even if free space is low.
-v Verbose output
-? Display this help text
-b Defrags the boot files only. Force all of your most commonly used applications to the edge of the hard drive for faster access
to use these commands
click start click run type
defrag c: -a -b -f
get the idea just seperate them with a space
and as Eddy stated defrag in safe mode. To do this press and hold the F8 key when you see the windows logo screen, right after the post screen …err… before entering windows.