Hm, did Firefox 30 get the Sponsored Tiles already? Rhetorical. I'm guessing that a new tab is opening alongside your home page. *Go to [[Image:new fx menu]] -> Options -> General tab -> Home Page section -> click <i>Reset to default</i> and type your own home page in.

Probably malware or the after effects of malware. It would also help to have had your full troubleshooting information, please post that then post back with the results of multiple scans with up to date tools. ------------ Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of. You can try these free programs to scan for malware, which work with your existing antivirus software: * [http://www.microsoft.com/security/scanner/default.aspx Microsoft Safety Scanner] * [http://www.malwarebytes.org/products/malwarebytes_free/ MalwareBytes' Anti-Malware] * [http://support.kaspersky.com/viruses/disinfection/5350 TDSSKiller - AntiRootkit Utility] * [http://www.surfright.nl/en/hitmanpro/ Hitman Pro] * [http://www.eset.com/us/online-scanner/ ESET Online Scanner] * [http://www.bleepingcomputer.com/download/adwcleaner/ AdwCleaner: (for adware)] * [http://www.kaspersky.com/security-scan Kaspersky Free security scan] * This one may be worth trying. It seems to have good reviews [http://www.herdprotect.com/ HerdProtect 68 anti-malware engines in the cloud.] You need to use multiple and up-to-date tools as they will not all pick up the same things. [http://windows.microsoft.com/MSE Microsoft Security Essentials] is a good FREE permanent antivirus for Windows 7/Vista/XP if you don't already have one. Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article. ------------ To find the correct solution to your problem, we require some more non-personal information from you. Please do the following: *'''For Firefox versions previous to 29.0''': Click the Firefox button at the top left, then click the ''Help'' menu and select ''Troubleshooting Information'' from the submenu. If you don't have a Firefox button, click the Help menu at the top and select ''Troubleshooting Information'' from the menu. *'''For Firefox 29.0 and above''': Click the menu button [[Image:New Fx Menu]], click help [[Image:Help-29]] and select ''Troubleshooting Information''. Now, a new tab containing your troubleshooting information should open. *At the top of the page, you should see a button that says "Copy text to clipboard". Click it. *Now, go back to your forum post and click inside the reply box. Press Ctrl+V to paste all the information you copied into the forum post. If you need further information about the Troubleshooting information page, please read the article [[Use the Troubleshooting Information page to help fix Firefox issues]]. Thanks in advance for your help!

You should Google your Utility Chest Installer Plugin(part of the troublesome MindSpark family) for information and removal advice. Does it do anything for you? Do you know where you got it?

Thanks for the help from various contributors. I have cured the problem by following the instructions to reset Firefox.