How can i fix my central locking fault on vauxhall vectra 04?

The keyfob will only open the boot, and the lock button
on the fob opens all the doors but wont lock them. the open button has stopped working. Also the dash warning display show's the drivers door is open when it is closed & the warning chime sounds when the key is in the ignition & when the engine is on when stationery.so the alarm & deadlocks aren't working. I've looked on the net but haven't seen a similar problem yet. I hope you can help me out as im getting my clutch & flywheel fixed at the moment so im hoping to find a cheap/free answer to the locking problem. Thanks