Using the back button to return to search results will always result in the browser asking you to re-submit the search. This isn't just on Ancestry, other sites including FindMyPast and The Genealogist will do the same. One way around it is to right-click on what you want to see, and then choose "Open in a new window" or "Open in a new tab" (if you have enabled tabbed browsing). That way you can get back to your search results without reloading.
P.S. You can adjust the text size on IE8 with CTRL and + and - keys, or if you have a mouse with a wheel, press CTRL and use the mouse wheel.