I have continual crashing of my Firefox browser since the transfer. The only clue is something called "plugin container" comes up. I can have a dozen or more tabs open on a hobby site, but when I open one or two forum stories Firefox crashes.
Would appreciate any assistance or hints for preventing the problem.
Sounds like you have a bad plugin. Ctrl+Alt+A
Click on plugins. Look for anything you do not need. Update any that are updateable. FR does not use anything odd other than google analytics and the whole freakin web uses that. Your problem lies on your machine.
Most likely easy fix: Sign in to Firefox Sync. Wait till it has backed up your settings. Completely uninstall Firefox. Reinstall and sign into sync.