Help please i have a problem with my fly sky nb 4

[Captain bart]

My flysky nb 4 was left in its box for the winter today i found that the batteries war completely discharged on recharge i found that it does not transmitt a signal to the receiver on the top of the screen ther is an RXwith a red Xin a box next to the tx battery indicator can any one describe to me how to fix this problem pleae its really bugging me we have good weather and i want to go run my car with the new max8 g2 combo i cant bind again as there is no signal being sent from the radio

[Mack1]

The only time I get the red x on mine is either no power to the receiver (no dodgy connection, or dodgy on/off switch or receiver battery is there?)

The other is the transmitter is on the wrong model.