post beep 1-1-4

I have a dell optiplex Gn running win95. It has the phoenix BIOS(older family). About 80% of the time when I start up I am getting a 1-1-4 combination beep. This is a BIOS ROM checksum failure. I cant get into the BIOS set up. When I press ctrl+alt+enter, it just takes me to a blank screen with a cursor. Some times my pc will start/restart sometimes it wont. When it doesnt it will just give me the 1-1-4 beep while the screen is black the whole time. It wont even boot from disk. I will have to unplug it, plug it in, ect until I get it to start up with out the beeps. What is a BIOS ROM checksum failure and how do I fix this.