Does it seem that the page has lost all of its layout, or both the layout and the content?

Have you noticed any other peculiar issues with sites in Firefox since you installed Windows 10? For example, have you gotten any secure certificate errors?

A unique issue affecting many Windows 10 upgraders is that they inadvertently enabled parental control on their own browsing, which causes seemingly random blockages. Try disabling Microsoft Family Safety (or not being part of a family): http://windows.microsoft.com/en-us/windows-10/turn-off-microsoft-family-settings

If I use Microsoft Edge instead of Firefox all is fine. On Firefox I only see white screen with a list of things in blue. Not sure why it would be fine on Edge. If security had parental control on wouldn't it effect both?

I couldn't tell you for sure why Family Safety affects Firefox and not Edge. However, my guess is that it is similar to the problem with other security software: it is easy for software to set up trust in IE by updating the Windows system certificate store, but Firefox uses a separate store so the software has to take an extra step to set up Firefox.

It's worth a try if you don't mind.

You can check the Net log and the Network log in the Web Console (Firefox/Tools > Web Developer) to see if content fails to load or possibly is blocked (file size is zero).

• https://developer.mozilla.org/Tools/Network_Monitor

Use Ctrl+F5 or Ctrl+Shift+R to reload the page and bypass the cache to generate a fresh log.

Try to boot the computer in Windows Safe Mode with network support.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10