I may have misunderstood, I think you mean you want to boot into some kind of environment where you can format your disk...?
What do you need to format it as?
You can't format it from within Windows? or whatever OS you're using?
I would use a live cd of Fedora (or some other Linux distro):
https://fedoraproject.org/wiki/FedoraLiveCD
Or this site has floppy and cd boot disks for windows, from memory (it's been a loooong time) the win 95/98 disks should have format.exe on them:
http://www.bootdisk.com/bootdisk.htm
Or maybe something like this:
http://www.911cd.net/forums//index.php?showtopic=24424