I'm replacing an old bryant thermostat with a new hunter digital.
I need help with wiring . 2 red , 2 white , 1 blue

What did the colers go to on the old stat? Should go back the same for a 5 wire setup!

You will have to look at the low voltage terminal board, even then it may not tell you anything.

You may have to use an ohm meter to find out which wire is which. To find out which is which, disconnect the wires from the thermostat and also from the furnace terminal board. Now tie the white wires together on one end, now touch your Ohm meter probes to the white wires on the other end. If your meter moves that will tell you that the two white wires go all the way to the other end. Now tie one white wire that you have marked with a tag that says "Gas" to the blue wire, if you meter moves you know that the blue is good. Now mark the blue wire with a tag marked "Fan"

Now repeat the process using the two red wires with the blue wire wire. When you have identified one of the red wires put a tag on it marked "Power in", the other red wire tag it with a tag that says "A.C".

I failed to tell you to tag the wires the same on both ends.

Now connect the wires as follows.

"Gas" to W on thermostat and furnace terminal.

"Fan" to G on thermostat and furnace.

"Power in" to Rh on thermostat and R at furnace.

"A.C." to Y on thermostat and to Y on the furnace.

Now you should have two wires coming from th AC unit outside, One wire will go on the Y terminal at the furnace and the other wire from outside will go on the "C" or "Com" at the furnace.

If this does not help let me know.