VinLew: I'm having the same problem, but this seems to be caused by a banner ad:
Win XP, IE 7, on an eMachine M350 with a screen resolution of 1024x600
Earlier I had an ad appear in the footer of the post (the black bar that has the 'like', 'tweet' and 'compose reply' etc., but I just thought it was nicer sitting there compared to in the middle of the post. The footer in this post fits on the screen perfectly - http://www.geekzone.co.nz/forums.asp?forumid=97&topicid=73677
Are you running any Antivirus that inspect web pages?
That leaderboard ad is in the wrong position. You should not see a leaderboard ad INSIDE any topic, it should always be above, like this:
One leaderboard above the topic, and one square on the first item of a forum page. If you see the leadeboard anywhere else, then something is interfering with the page.
Also I suggest you update to IE 8.