Am installing a new thermostat but there is no existing thermostat, just the wires coming out of the wall, Red, White, Blue and Yellow.
I hooked the Red to R/Rc, White to W, Yellow to Y, Blue to B. the blower comes on and the Thermostat does not display anything on it?
Could you guys help please.

Check to what the blue wire is connected at the furnace. My guess is it will be connected to "G". If so and you have A/C on the furnace, you will need to get a thermostat which is battery powered.