Windows 7 IE11
The problem (most likely - it usually happens with Win 8, but I've seen it with 7 and IE11) is Internet Explorer 11.
It's a "rolling train wreck" as far as code and browser ID goes. There are literally THOUSANDS of websites and pages that can't and don't recognize it... as IE or anything else for that matter.
So far, Microsoft has made NO indication that they have any plan to fix it soon. In fact, the refuse to even acknowledge that their browser has a MAJOR problem.
Microsoft's recommendation is to use Compatibility View for affected pages, and "pretend" you're using an different browser. Trouble with that is, it's seen limited success at best, and you have to individually enable it for EVERY page that has problems.
I'm not big on "pretending" so I recommend actually using another browser.
ANY of those will work where IE11 won't, with the Flash Player Plug-in (For all other browsers), and Chrome doesn't even need that because it has its own Flash Player plugin built in.