Top half of page is black

Out of the blue, the top page of my website ICCNS.CA is black. First it appeared on just Firefox, but now happens on Safari as well. When I disable Javascript – problem disappears. So I took java script code out of header but that did not resolve problem.

Apparently this is just happening on random computers – not all??? I’ve using a iMac OS 10.5.8, with all updates installed. I’ve validated the CSS to see if there was something there causing the problem, but couldn’t find anything. Totally baffled and confused.

Any advise would be greatly appreciated!

DCameron