I have site which is working more than fine at firefox,

Hi, I have site which is working more than fine at firefox, chrome and so on. But in IE it's not working at all, could you give me some hints how to fixt it even for IE 9 (and maybe some older versions, I don't have them unforunately). I have never done that before in that big difference as it is right now.

The site is here: http://baseta.cz
Thanks a lot in advance