Cubase SE

HI. Still using the old Cubase SE system but recently had some work carried out on the laptop and now all playback of existing stored files is accompanied by a constant crackle. I have tried playing music through I-tunes and no crackle so definitely within the Cubase system. Any ideas?

What are you using for your ASIO sound source selection within Cubase? What are your latency/buffer settings?