Until recently I was not able to see any flash content (Soapbox videos, e.g. ;-) in my browser on my Vista machine. Adobe's installer site told me that everything was fine, but other sites complained that I either had not installed Flash, or turned off JavaScript (which is both not true).

So the problem behind this is Vista's User Account Control (UAC) which, on installation of the Flash plugin, can't modify certain registry keys (even though you are an admin), but doesn't tell you about the failure (which is not a good thing).

The solution? Go to "C:\Windows\System32\Macromed\Flash" and right-click on FlashUtil9b.exe, the select "Run as administrator".

Afterwards, you should be able to view Flash content in the browser.

HTH.