On YouTube, I get the following message "Old Flash, get upgrade." Here are the details,

Windows 7
No firewall or antivirus running
Have enabled and disabled AdBlock, Flash Block
Have uninstalled and reinstalled latest version of Flash.
Have subscribed and unsubscribed to YT HTML5

Nothing works.

Please don't message me with suggestions to do what I've already done. Like I said, Flash works, but for whatever reason, when I'm on YouTube, it will not play. I can even play a video that has been embedded from YouTube, as long as I don't go to the YouTube site itself.

Firefox and IE both work with YouTube, Chrome does not, which is a shame since it's so much quicker. However, if I can't use it with YT, there's no point in keeping it.

What is the version of Chrome that you are running?
Go to the Wrench and select About Google Chrome

Sometimes on YouTube, the video plays, but I can't see the player or video until I scroll the page around. I could hear audio though..so if you can't that's probably not the problem. ><

Try opening a Safe Tab -> ctrl+shift+n
and see if problem remains