When I try to modify a view, I get a screen full of odd text
This is caused by a JQuery AJAX failure.  Several different things could be causing this.  You will probably need to research the current active theme and any modules that you are using in or around that view (especially ones that use AJAX) to see if they have a history of AJAX related failures (and related fixes or patches.)  A few things to try:


Enable, disable or change the settings within the jQuery Update module (some versions of jquery are not compatible with some modules.)
Change the theme used on admin pages to a generic theme (included in the Drupal download)