A few problems with my site I'd be grateful for help with...

Question

Hi, I'm encountering some strange problems with my website, and I'd be really appreciative if anyone could help me. The site's live so I've included links to help anyone kind enough to respond. Thanks in advance.
1. On many of the pages, a scrollbar appears at the width of the container as opposed to the browser window. The 'clear' property doesn't seem to work, (although I am quite new to it so could have made some sort of basic error).
http://austinlindsay.com/suretowin.html
2. I'm having difficulty with the 'screenshots' on the left hand side of the page. First, the larger images should only appear when hovering over the thumbnails, but they seem to appear when hovering over the space where they appear.
The second problem is trying to make the background of the larger images consistent with their individual images in the foreground. Problem is the background always have a fixed width across the page. You can see what I mean when hovering over the final screenshot (called 'Scoreboard')
http://austinlindsay.com/virtuoso.html
Two problems with the 'Featured' section. The central link jilts slightly when hovered over. It's really strange. I've tested it by changing the order and putting a different link in the centre, and found it's not a problem with a link, it's a problem with it being positioned centrally. I couldn't find a solution for it, though. The final problem with this is that a horizontal scrollbar appear when hovering over any of the links (apart from the final one, Logos, for some reason).
http://austinlindsay.com/
I know there's a lot of problems here, but thanks in advance to anyone who can help!

Answer 1

No, there is definitely no height property on the container (or the content which is causing the problem). But to be fair,  it may be because the content that gets hidden is, until hovered over, not visible. I've posted the code for that below, along with the container if anyone could help?
/*main container*/
#content {
    position: relative;
    left: 0px; right: 0px;
    width: 960px;
    background-color: #333;
    padding-bottom: 3em;
    border-top: 0.1em solid #FFF;
    border-bottom: 0.1em solid #FFF;
    overflow:hidden;   
/* container for the screenshots content below this*/
#main_content {   
position: relative;
margin: 0 40px;
top: -160px;
/* screenshots - content that seems hides itself*/
#screenshot_list {
position: relative;
left: 72px;
#screenshot_list a {
border:none;
text-decoration:none;
padding: 5px 0px;
display:block; /**space between icons**/
position: relative;
width:150px;
#screenshot_list a span {
visibility:hidden;
display:block;
position: absolute;
/**adjust positioning of full size images in px or %**/
left: 130px;
top: 0px;
/**optional image captions**/
font-size: 13px;
line-height: 1.2;
color: #FFFFFF;
text-align: left;
background-color: #455c5a;
background-repeat: no-repeat;
/**optional image borders & padding**/
border: 2px solid#455c5a;
padding: 15px;
z-index: 100;
#screenshot_list a:hover span, #screenshot_list a:active span, #screenshot_list a:focus span {visibility:visible; z-index: 100;
padding: 15px;
#screenshot_list a:hover, #screenshot_list a:focus
{visibility:visible;
border: none;
z-index: 100;
padding-left:2px;