CMOS Settings Wrong

The machine I am working on is a small desktop Gateway 800Mhz with only USB connections. When I go to boot up, the message comes up, CMOS Wrong.
I have pressed the F1 to get into the BIOS and there is NO response from the Keyboard(USB) I understood that USB isn’t recognized in DOS, Is this true?, If so, what is the work around?
HELP PLEASE