Yes Donna, disconnecting the battery for 24 hours will not help you at all. Your alarm panel has what is called an NVM chip, this chip is the memory and holds information with or without power. They do fail but it takes years.
To reset the code is quite easy, i helped someone yesterday from this site to do the same thing as you.
Im on 07842 480037 my name is Nick i will talk you through it.
Nick
September 2009