trouble since php 5.3 upgrade

My server upgraded to PHP 5.3 recently. First, my site didn’t work at all, then they told me to remove the php.ini file. The site came back then, but, it is quite twisted. The front looks strange, with lots of text that belongs to other places on my site, and I cannot access any of the sub menus. I am not a skilled programmer, so I’m pretty lost when things like this happens. Hope someone can help me.
I use twenty ten theme, wp 3.3.2. My site is here: https://www.helgelien.com