I have an older laptop I'm going to give away and would like to wipe the hard drive before doing so, if possible. The laptop contains only one hard drive. Is it possible to wipe the drive containing the operating system? If so, how and what software would I use to do this?
If you're not concerned about NSA-level security then what I'd do is boot from the OS install disk, choose the custom install option, and do a full format of the drive. Then eject the disk and shut down the computer before the OS actually installs.
That will prevent anyone from reading the contents of the drive short of taking it to a clean lab, opening it up, and using extremely specialized equipment to do a forensic analysis of the residual magnetism under the newly-recorded "0" bits.
Take a peek at this: http://www.zdnet.com/blog/storage/how-to-really-erase-a...
A while ago, the ability to "secure erase" a drive was built into most hard drives. I have no experience with how "secure" it is; for all I know, a good lab could recover some data. But it's fine for "casual" use.
I'm so paranoid that, when I through out a laptop, I took the drive out and broke the platters. Talk about "disk fragmentation."