how to reset my alarm?

Reset codes are programmable, usually 4 digit number, that makes for 10,000 possibilities.
You will need to reset the system to factory default then use setup code (I think it's 1234 on a Wickes system) to reprogram the parameters and your personal code.
The bad news is you will need the programming manual to achieve this.
I have a manual for an early wired Wickes alarm system but not to hand,if you can leave the model /type no of the main pcb here I will see if what I have will help you out,if so I'll photocopy it and post it to you.

Pete
October 2007