howcan i fix my corsa y reg?

my central locking is playing up, when i try to open with fob the drivers catch jumps up and down but the others do nothing. but when i use the key clicking twice they all open. to lock i can use the fob which will lock all doors and boot. i can not open the boot with the key not sure if this is part of the problem as until this as been going on iv never used the key to open the boot . i bought the car second hand six years ago so unsure if the the boot problem was there then.