.htaccess causes pages to not load fully

[Mallee Boy]

Hi,

I have upgraded from 115 to 125 with reasonable success. However. When i create a blank .htaccess, turn on friendly urls and then "generate" the .htaccess file in tools, my pages (front and back) immediately begin to slow down and dont fully load. Friendly url is working in front end but the pages take forever to load. I noticed that if i delete the .htaccess that the pages load in a second (both front and back end).

Any help?

I also noticed that (regardless of my .htaccess file) the back end does not seem to load properly - see the tabs, no icons and general mess around the menu buttons.