Type of formatting

hi guys
i wanted to create a windows 7 repair disk from one computer to try and fix another friends computer that will not boot after he partitioned it. I have bought a dvd disc and my question is, which formatting should I use on it before I burn? should I format it for use as a usb? if I format it for use like a usb can I use it as a bootable disc for other software ie linux operating systems? if this is possible please tell me as it would save me on buying DVDs.
regards
Juggernaut747