No video signal

Hi I have been using a Byte Plus very well for years. Today I changed some settings in Bios and my Byte Plus doesn't give any video signal after that. Even Bios doesn't show. So I disassembled my Byte Plus and disconnected the cable of the flat battery from the main board. I waited for more than 10 minutes and powered my Byte Plus on hoping that Bios has been reset. But it doesn't give any video signal at all. Is there anything I can do to fix my Byte Plus? Please help.