Just roll your mouse over the facebook and share icons and the page will break in IE7 very badly.
The whole page really needs ot be revised if you want to support IE7 as you have used multiple flawed concepts to build it.
For example in many many items you have made the inner content wider than the parent container. (e.g. #connect is 278px wide but the inner welcome element is 320px wide the same for #intro.). In older versions of IE when you increase the inner then the outer element also increases thus breaking the layout.
The solution for IE is not to add a width but to drag the element wider with negative margins instead and then apply haslayout with zoom and position:relative as without those the overflow portion becomes invisible.
IE likes everything to add up nicely or it won't play nicely.
We can cure the footer problem which is actually caused by the welcome div overflowing and causing a chain reaction.
Add this to the css file:
margin:0 -40px 0 0;
However, we can't cure the page jumping without a page re-write as the current set up is just too unstable for IE.
You really need just two floated columns and not multiple left and right columns as that causes snagging when they are uneven and the fact that you have added heights makes no difference to IE as it will stretch the content anyway. You should let the content dictate the height for elements that hold text.
There are also many containers without haslayout and when containers hold complicated content they need haslayout which can be applied using zoom:1.0. However applying it willy nilly will may have detrimental effects also so its really something that you shuld have built in form scratch as you were testing.
If you want to support ie7 and under then I would suggest that you make two floated columns only of the correct width. Then make sure that inner elements are not larger than those parents. For your folds you could place them absolutely into position as you have done for some of them and use negative margins for the h3 to drag it wide but don't apply a width.
Sorry I couldn't give you a full solution but all my "silver bullet fixes" failed due to the way everything was set up.