How Do I Reformat my Hard Drive on Windows 2000?

[Marcus]

I cannot reformat the Hard disk on my Windows 2000 laptop. Once I enter DOS and type "format C:" then "y" It then says another volume is in use, not allowing me to reformat.

I appreciate Any Help and please forgive me for asking a stupid question, I'm not good with computers.

[Computer_Commando]

I cannot reformat the Hard disk on my Windows 2000 laptop. Once I enter DOS and type "format C:" then "y" It then says another volume is in use, not allowing me to reformat. ...

You're not allowed to format while the OS is in use.  
You'e not allowed to change the engine oil in the car while the engine is running.
http://www.computerhope.com/issues/ch000544.htm

[MalikTous]

In BIOS, set the CDROM to the first boot device, and boot to your Win2K CD. Then you can use the installer options to delete and remake the partitions, then format it in NTFS, and re-install the OS.