hello, please see if any of the solutions in How to fix preferences that won't save can address the issue.

You can also do a malware check with some malware scanning programs on the Windows computer.
Please scan with all programs because each program detects different malware.

Make sure that you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  http://www.malwarebytes.org/mbam.php
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  http://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender: Home Page:
  http://www.microsoft.com/windows/products/winfamily/defender/default.mspx
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  http://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• http://support.kaspersky.com/viruses/solutions?qid=208280684

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

I had a similar issue, my web-browsers got hijacked and pop-up windows thrashed my work, finally i found a free program :

http://www.bleepingcomputer.com/download/adwcleaner/

it worked miraculously after a restart I own my computer again. I did spend more than 20 hours with not so helpful advise.

The program removed all malware and freed my hijacked web-browsers.

special thanks to the nice guys in France for the program

Hi edelres, thanks for that. Just a note to anyone visiting that page who isn't using an ad blocker: you want the free AdwCleaner available from that page, so ignore the colorful banner ads that take you away from the page (or come right back if you click one of those).