Your system should be ok, your control panel backup battery has failed. What's displayed is classic symptoms of backup battery failure.
If you had the LED keypad then it would be lit up like a Christmas tree, same issue battery failure :)
Take a look at your control panel, see the two screws, one at either side holding the lower portion of the panel on?,
The battery is accessed by removing that,
Please for your own safety switch the power off to the panel before you remove this cover, should have a fused spur fitted, pop the fuse out of that, or turn lecky off at main fuse box.
Battery details are written on it and it's a simple case of buying new battery, only two wires to remove from the battery.
Remember red wire goes to the +(positive) terminal on the battery when you fit the new one, black is - ( negative) :),
Hope this helps, be safe and good luck.
e manno
August 2012