No Flash Player!!

It can be very frustrating as a web designer to create amazing Flash content, only to find out that many of your viewers do not have Flash installed.  There are a couple ways to get around this. 

1.  If you have a site that is completely designed in Flash, then you will need to use the javascript option listed below.  The reason for this, is that unless you want a single image to replace your entire site, you will need to redirect the user to an alternate page that does not contain Flash. This option creates more work for the designer/developer because you'll actually be constructing two separate sites.. one for Flash, and one for HTML alone.  

2.  This second option works well for any site that has Flash content only as a header, or other singular part of a site.  The majority of the site in this example should be HTML, with limited Flash content added.  This technique uses a line of HTML code that will swap the Flash content for an image anytime that a Flash Player is not detected.

Links and Code for Flash Detection:

(Also try searching Google.com for Flash Player detection)

Adobe Flash detection kit

Flash detection script for Javascript or HTML