CSS Cross Browser Issues

I need a realistic budget do not bid if your gonna bid silly money. I have some cross browser issues that require resolving, please see below for more information also see attached zip file with screen grabs: INTERNET EXPLORER 8 1.) In IE8 the View cart page, when the screen resolution is reduced there is overlapping. See image B. 2.) The JS error i sent in IE8, when you click the 'continue' button without selecting the required fields you get this error. See image C. 3.) In IE8 the category page, when you mouse over the products there is a shadow issue. See image D. 4.) In IE8 on the category page when you move your mouse over the top row of thumbnails it causes the thumbnails in the row below to move. 5.) In IE8 there is an issue on the product page, the two columns don't seem to be re-sizing accordingly to fit side by side. See image G. ALL BROWSER ISSUE - IE8,9,10,11 - FIREFOX, SAFARI & CHROME 6.) The thumbnails on the category pages when the COLUMNS CHANGE TO 3, the images are no longer proportional they are being stretched. This issue is in all browsers and versions. See image A. 7.) On the product page when you re-size the browser window there is overlapping, this is fine with the base image however when you select a different 'design colour' there is overlapping. ALL BROWSERS. See image E. 8.) The Live Chat link in the main navigation bar, when the screen gets smaller it is supposed to disappear. See image F. 9.) On the homepage the featured items thumbnails, when the you start to re-size the browser window the thumbnails start to overlap a little. See image H.