Remove the ubcd cd from the cdrom station.
Power down the PC completely. Remove the power cable (to be sure that the pc doesn't contain any electricity) and put it back in.
Power up the pc, hopefully it works now or at least the BIOS.
If not, power down the PC completely. Remove the power cable. Remove the cmos
battery on you mobo (search the internet for more information), put the battery back in place after a minute or so (a few seconds should be enough. Check also if all connectors on your mobo are connected properly (should be right normally).
Power up the pc and pray
Normally booting to freedos shouldn't chance anything to your BIOS, unless you have done a BIOS update from within freedos of course.
After using UBCD to boot into dos mode, my computer just beeps (short) continuously without stopping.
Do you see any text messages? Write it down or take a picture and post it, so we can get an idea.