One cause of this problem seems to be a little program called "Google Web Accelerator." This is a program that many people are using to speed up their web surfing. Apparently it works well for many, but it is currently messing up a few people's ability to view YouTube videos. If you are using Web Accelerator, try turning it off and see if that helps things.
Another tip to try come from my friend Rob who manages technical and customer support at islandnet.com. Here's what he suggests (as copied form his comment below):
I was told the solution for this is to:
- Go into Control Panel
- Go into Internet Options
- Go Into Connections
- Click Lan Settings
- Uncheck "Automatically Detect Settings"
- Click Apply/Okay
This works for highspeed users so I am told, I have not verified this yet.
So there you have it. Give those a try and let's see if they work for you