Firefox questions

Two questions:

1) I'm confused about Firefox versions. Is version 11 that much different than version 4? I completely missed versions 5-7, then had terrible problems with version 8 trying to install itself automatically. It was loading something like 1 gb in the task manager and climbing and using a huge amount of the resources, so I finally got it out and went back to 3.6.

2) On a different computer, I installed a newer version of FF and ever since then, even after getting rid of it and going back to an older version, I cannot get the yahoo login screen to dismiss my email address with the login autocomplete (?) box anymore.

As soon as I type a letter into the login name, my complete email address shows in the auto dropdown. I've set FF not to use this form of autocomplete, but it seems obcessive about keeping this one login name.

Yahoo says it's not something they are doing, that it has to be from Firefox, even though it doesn't happen with any other website. I use CCleaner religiously, but it doesn't get rid of this. Can anyone advise me how to get rid of this autocomplete?

 

I don't know how to just get rid of only this Yahoo autocomplete but if you want to get rid of them all you could try this

FireFox Options > Privacy
To the right of FireFox will: select Use custom settings for History
Tick Clear History when FireFox closes
Click on Settings and tick Form & Search History and whatever else you want to clear when you exit FireFox
Click OK
Click OK on the next window

If you want to always clear everything when you exit FireFox the best way is to go to the Privacy tab and tick Always use private browsing mode
If you are going to use Private Browsing Mode you will probably want to clear all your History and Forms etc that are already saved.
FireFox > Tools
Clear Recent History (Ctrl+Shift+Del)
To the right of Time range to clear: select Everything
Click on Details and make sure everything is ticked
Click on Clear now
Restart FireFox (might or might not be necessary)

 

I wondered if your instructions would throw me out of Majorgeeks if I followed them. They did. lol
I appreciate these ideas. They're great!