I'm trying to reformat my hard drive. When I type format c: I get bad command or file name response. What can I do?

Try making a Windows boot disk, booting from that and then wiping your PC. What version of windows are you using? I'm thinking Win ME.

If it is Win ME (or earlier), get a boot disk from here - http://www.bootdisk.com/bootdisk.htm

I'm using xp and have boot disks, but I get an unrecoverable error and it ejects my disk.