Clear the cache and the cookies from sites that cause problems.

"Clear the Cache":

• Tools > Options > Advanced > Network > Offline Storage (Cache): "Clear Now"

"Remove Cookies" from sites causing problems:

• Tools > Options > Privacy > Cookies: "Show Cookies"

Start Firefox in Use Troubleshoot Mode in Firefox to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

What is the method you are using to navigate to the other site? Are you entering a keyword such as youtube into the url bar and pressing Enter?

Does it work if you use a bookmark, or if you type youtube in the url bar and pause until your list of recently used sites comes up and chose a YouTube URL from the list?

Google operates a DNS service that you can use in place of your regular ISP's DNS servers. Do you recall ever trying out their service? Note: this might be set up in your broadband router rather than on your computer.

Guess you've quickly figured out I'm no computer genius.

Doesn't matter if I use a bookmark or type directly. and doesn't happen every time. But now that you mention it, I notice it more on the Clearwire connection. I will take the old laptop out this week end and see if it happens on some other access points.

Thanks Guys, we're getting somewhere. I will follow up on what I find in case it helps anybody else.