[SOLVED] Options not displaying now System/Products

Hi, I just upgraded from 1.5.0.5 up to 1.5.1.3 and have had a few issues.
All have nearly been sorted out. One was as a result of not having my tax classes setup.
When I have gone into look at them, my System settings has all disappeared with the exception of the initial tab. The same with my Product Options Tab as well. I have attached pictures of the screenshots. Everything has been enabled in User Groups, & I have checked using Chrome & IE.

Any ideas? I have been tearing my hair out with the other issues, now I can't edit my products (though I can through Ecommerce manager on my Android Phone).

Hi, after much searching (and there was no easy way to look for this - too many common names). I found the answer here:-
http://forum.opencart.com/viewtopic.php?t=41337
I reloaded all the admin files (except config.php). The only thing I can think of is the new checkout.tpl file I uploaded to check for errors, must have upset the balance.