I take it from your reply that your entire harddisk, with the exception, possibly, of a "D" partition for recovery, is also your C partition. You need to create partitions as virtual "sub-disks" using Windows itself or a program such as Partition Wizard.
Make your C partition (the one with Windows) about 80 gb for Win7. That's the one you want to defrag. Note that other partitions (E, F, G...) must be created for data and application defaults (Office) changed to one of those non-C partitions otherwise your C "disk" will fill up quickly. Your data partitions don't need to be defragged at all, or once every 3 months. Here's my Partitions on my WinVista (Control Panel>Administrative Tools>Create and format hard disk partitions)
HP C: (System, Boot) 41.35 gb
D: Recovery 6.27gb
E: MyDocs 50.78 gb
F: Multimedia 146.24 gb
G: Swap 9.76 gb
H: Audio 107.87 gb
I: Backup 19.53 gb
Note: These don't add up to 500 gb because I have some un-allocated space. The system partition (C
should be defragged once per week using a third party application (e.g. Auslogics). Never use Window's defrag because it doesn't work right. Disable it, take it off auto, and forget about it. Never defrag Recovery (D
. As for E:-I:, you can defrag them during lunch once in awhile.
If none of this makes sense, you should educate yourself on basic hard disk operations.