If your phone is on an Android version higher than 4.3 then you can use Smart Switch to connect to your PC, available via the following link: http://www.samsung.com/ie/support/smartswitch/. If you've tried that and you're still unable to connect then please can you let me know what error messages, if any, you're seeing when you attempt the connection?
Have you tried connecting your phone in Safe Mode, @ben160? To activate this, restart your phone but whilst it's powering up, keep the 'Volume Button' held down until you reach the home screen. If done correctly, Safe Mode will be displayed in the bottom left corner.