Hi, this is unlikely to be connected with your update - it sounds much more like a malware issue. So you can try these free programs to scan for malware, which work with your existing antivirus software:

• Microsoft Safety Scanner
• MalwareBytes' Anti-Malware
• Anti-Rootkit Utility - TDSSKiller
• AdwCleaner (for more info, see this alternate AdwCleaner download page)
• Hitman Pro
• ESET Online Scanner

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Note that not all removal programs will detect all malware, so you may need to run several or all of them.

After removal you may need to reset your home page, search etc., which you can do by running the add-on SearchReset.

Did this fix your problems? Please report back to us!

I agree it sounds very malware-ish. Could you also describe the steps in a little more detail, for example:

• are you searching using a Firefox bar and if so, which one (e.g., search bar, address bar, home page bar, new tab bar)?
• if you are searching directly on a search site, which one is it?

Could you check your download history to see whether Firefox shows any unexpected downloads?

In addition to using automated clean-up tools, I suggest:

Open the Windows Control Panel, Uninstall a Program. After the list loads, click the "Installed on" column heading to group the infections, I mean, additions, by date. This can help surface undisclosed bundle items that snuck in with some software you agreed to install. Be suspicious of everything you do not recognize/remember, as malware often uses important or innocent sounding names to discourage you from removing it. Take out as much trash as possible here.