Site off on MacBook Pro

[simplyimpressive]

I designed a site for a client, and during the whole design process, they were complaining that the items were “below the fold”, so I would arrange them to be “above the fold” but it just didn’t look right to me. We published and they were happy (although I wasn’t). Well we are now changing background photos and changing things up a bit and the same issue is occurring. Where I see things placed perfectly, on their end it’s all off. Very frustrating. I asked what they were viewing the site on and they said a MacBook Pro. This is the first time this issue has come up and I am quite baffled. Does anyone have any advice?