Use F8 to select open in MS DOS only. I have no idea what prompt letter will come up. If it is C then you won't be able to F disk because you can't wipe out the disk where the DOS files are stored.

Maybe it creates an artifical A prompt. The system files [DOS files] should be on the hard drive but maybe it creates a RAM drive. Pure WAG on my part.

BTW didn't you get a recovery CD with the machine??? Most proprietary systems give that rather than the actual Operating System disk. The purpose of the recovery CD is to do what you want.