In order to know the difference between the bank balance and the trial balance. You should print a statement of account from the accounting system for the period from 1-1-2008 to 31-12-2008. And the you should have a bank statement from 1-1-2008 to 31-12-2008. After that you should start from the beginning of the two statements and start to check that every movement in the bank statement is recorded in the statement of account. For example if there is a debit movement in the bank statement then there should be a credit movement in the statement of account for the same amount (if it agree just tick it on the two statements) then after checking all the debits and credits for the year there will still some movements that are recorded in your books but are not recorded in the bank and also there will be movements recorded in the bank statement but are not recorded in the books then you should highlight these movements to see why they are not recorded.