I realize there's been an upgrade to the Flash player.
I have a client whose web site is built in Flash, however, and all that appears for her and most of her audience (PC, I think) is a blank screen -- no alert to let the users know that an upgrade is available.
Here is the web site:
I would like for users with outdated Flash players (or perhaps Internet Explorer) to try this link and let me know how I can fix this issue.
In general, Flash Player is backwards-compatible. A new upgrade shouldn't render the site useless. My guess is that changes to Internet Explorer are actually at the root of the problem, but a survey of what configurations the site does and doesn't render under would be useful in understanding what's happening. At a quick glance, I see that there are some conditional comments in your HTML, which IE no longer supports.
You might want to take a look at using SWFObject to embed the SWFs instead of using the Object/Embed tags that you're currently using:
This may also be related to ActiveX filtering in IE. When I view the site in IE11, I get the prompt asking if I want to show Flash content. Once I allow it, the content renders as expected.
There are a bunch of free tools for testing against Internet Explorer over at http://modern.ie/. They might be useful in helping you modify your site to be compatible across IE versions.