Only the c: partition would be affected by "format c:". But it is your boot/system drive, so don't expect the machine to boot from the HD after it. Probably best to do a clean boot from a diskette or some such before formatting the c: drive. Reinstalling the OS <i>and</i> apps, or installing new OS and apps?
<font color=green>I haven't lost my mind. I know exactly where I left it.</font color=green>