iphone 4 unlocking problem

i have an iphone 4, it says it is disabled and needs to be connected to itunes, however when i connect to itunes. it cannot unlock my device because of my dads old passcode on it. When i place the phone into recovery mode however, my laptop recognises i have plugged the device in, although my itunes is oblivious and i cannot restore / reset / do anything with the iphone. I have updated my itunes, reset my laptop, stopped / started apple device management software. Everything i can find but absoloutely nothing is working - any help i would be more than grateful 🙂