Yep, there was an option in DOS to wipe the drive, then it disappeared until Vista was released. I use DBAN (Darrick's Boot And Nuke) on older systems.
Change dump file size:
<Start>
<Control Panel>
<System>
<Advanced><Startup and Recovery>
<Write Debugging Information>
The options are:
(none)
Small Memory Dump (64KB)
Kernel Memory Dump
Complete Memory Dump