Please see these articles:

• Home page with pipe character opens extra tabs when Firefox starts
  
  
• Firefox repeatedly opens empty tabs or windows after you click on a link
  
  

If this suggestion resolves the problem for you, please click the Solved it button next to this post after you log in into the forum. This will help others searching for a solution to the same problem.

Thanks.

well, i did what u said, didnt help. my home page is www.yahoo.com. nothiing else.ive uninstalled firefox twice, and reinstall. still keeps opening up allot of my plug in. right now, everytime i launch firefox, my home page opens up, then a new tab opens up(which want let me close out for some reason), cooliris, xmarks, silverlight tab and xmarks tab opens up.it really irritating me now. and when i try to close the tab that says new tab, firefox stops responding. this never happened until i went from version 4 to version 5.i have no idea why so many tabs are opening up. like i said earlier, ive looked at all the setting and everything looks like it needs to be, i dont see a reason to put a pipeline. i have no idea whats going on. maybe i should just uninstall version 5 and just stay with version 4. i really hate internet explorer and google chrome, not a fan of opera, but i running out of options. i really dont wont to disable everything just to keep all these tabs from opening up on one page. i appreciate any more advice to help. thanks

Try running Firefox in Diagnose Firefox issues using Troubleshoot Mode. If it functions properly in that configuration, then one of your add-ons is the culprit.

i dont have a safe mode. i use revo uninstall. when i reinstall, all i get is mozilla firefox. when i had version 4, i remember it having firefox and firefox with safe mode. when i installed version 5, safe mode was gone.i just figured it was a change when it upgraded from 4 to 5. like i said, ive uninstalled it twice, and when i reinstall, all i get is firefox. no firefox with safe mode.

All Firefox versions have a debugger (Safe Mode). Click Help | Restart with Add-ons disabled, then when you see the menu, click "Continue without making changes".

Firefox will subsequently restart with Add-ons disabled. You can then test it in that configuration. If no tabs open unexpectedly, then one of your Add-ons is causing the problem.

See the article I linked to. Here it is again: Diagnose Firefox issues using Troubleshoot Mode

See:

• http://kb.mozillazine.org/Preferences_not_saved

ok, well, i finally did a complete uninstall using revo uninstall. rebooted. downloaded and installed new version of firefox and all seems to well now. i had noticed that i kept getting this tab saying firefox has a new update that needs to be installed. not sure if thats what messed it up or what. but, i got it working again the way i want and am happy once again.firefox rocks. i dont understand why people are still with ie or opera. crazy. got a new question. i have the droid x2. right now im using the stock browser because i seldom get on the internet. i was wondering if the mobile app is like the the desktop app. if i use the firefox app on my droid x2, does it have plug ins or add ons that will allow me to download youtube videos. there r NO apps on the market and a couple browsers say they can/or use to like dolphins browser and opera. since im familar with firefox, if they have an addon that will let me download youtube videos, that, well, would be awesome. just wondering if its possible. like video downloader or something else? thx