Ultimate Boot CD

Thanks to UBCD, I've cleaned up the old OS from the hard disk (c:). Then I partitioned it to fat32 with fdisk. Now I'm shot in the dark I don't know what to do to make my hard disk bootable again.
When I boot up without UBSD it says:

Disk not bootable

I tried "format c: /s" but it said "No SYS in PATH".
Please help me, I really don't know which tool to use on UBCD to make drive c: bootable. It's the first time I've used UBCD so I'm a beginner.

Well you've got to install an OS on it... or at least copy the system files from it.

You may copy theses files from the FreeDOS boot disk : Kernel.sys, Command.com
That should be enough to boot and get a command line interpreter.