you can't without the cd
Your hard drive is assessable thru CMOS without a password
Use ErAce from erace.it
To completely erase the data on the hard drive.
To completely erase the information on your hard drive, you can try a third-party tool like iReaShare Data Wipe, which can completely erase your files, folders, hard drives, and external devices on a PC.
Use ErAce from erace.it
Reinstalling Windows will not erase the hard drive unless you tell it to reformat the hard drive before reinstalling the operating system. You will have to reinstall all your programs that were installed prior to reinstall but all your saved files will still be there.
It can erase your hard drive!They can delete your files.
You can use over write programm like ErAce form erace.it
An external hard drive can only be connected to a router with a USB port. Consider Asus routers for hooking up external drives.
Degausser
The most conventional way is to get a giant magnet, and slide it across your hard drive atleast 7 times. WARNING: Only do this if you truly want to destroy/erase it.
dd if=/dev/zero of=/dev/hdxSubstitute the appropriate drive letter for x. Be very careful that you do not erase the wrong hard drive.