After removing 3.6.17, you can install 4.0.1 without losing bookmarks, customizations etc.

If you don't like it, then simply remove it and reinstall 3.6.17

Here's the procedure with links to both downloads.

1. Go to Download Firefox 4.0.1 and download a fresh installation file to the desktop.
2. Go to Download Firefox v3.6.17 and download it to the desktop.
   
   
3. Then go to Add/Remove Programs, scroll down to "Mozilla Firefox" and remove it, choosing to keep your bookmarks, customizations etc., (don't checkmark the box).
   
   
4. Then reboot and delete the folder called "Mozilla Firefox" at this location: C:\Program Files\Mozilla Firefox
   
   
5. Finally run the installation file you downloaded to the desktop earlier.
   
   

Your bookmarks, customizations etc., are maintained in a different location and will become available to you again once you complete the installation.

Firefox 4.0.x is radically different than previous versions, but you can change it to look like its predecessor like this.

• Right click a blank part of the tab bar and click "Tabs on top" to remove the checkmark. Tabs will subsequently reappear below the search bar.
  
  
• Repeat the same steps, but click the top one called "Menu bar". This will reinstate the text links at the top.
  
  
• To rearrange the layout, repeat the same steps again and choose "Customize". A panel will open and while that remains onscreen, you can move elements like toolbars, buttons etc around and place them anywhere you wish. You can also drag anything you don't like into that panel and add anything you want by dragging it out of there.
  
  
• To replace the status bar at the foot of the page, install this add-on: https://addons.mozilla.org/en-US/firefox/addon/status-4-evar/
  
  

Thank you for your help. I was hoping that I could keep 3.6.17 up and running for my daily work and have the new version there when I have a chance to try it out. I'm online and working 10 to 12 hours a day and don't have a lot of time to experiment and play around.

Again, Thank you for your help.

RJGraham

You're welcome.