While driving down the highway my MPG and RPM Gauge suddenly go all the way to zero and the transmission starts running funny. I drive it the remaining 3 miles and shut it off. Try to restart it and it won't start. Put a jumper on the battery and it reads failed. Buy a new battery and put it on and it starts and runs fine. However, the MPG and RPM gauges still do not register. Also if you turn the headlights on they "beep" continously while driving, as they would if you turn the Blazer off and leave the lights on. Any ideas?

Welcome to AF.
The 97 has a lot of ign switch problems.

Check for good power coming out of ign switch and to fuse boxes with key on.