A little investigation can help with the problem.
There are tons of Anti-Virus and Anti-Malware programs out there that attempt to lock your browser, home page, and address translation websites. It would be good to open each/any of these programs and see if there is a setting for this option.
In addition, there is Malware, including the Google and Firefox Redirector versions, that can cause similar problems. If your searches are directing you to unwanted or odd sites, you probably installed one of these Trojans, and will need to stop this process and follow up with that issue
. Since these malware products normally accompany an authorized download presenting as a browser add-on, it can fool many protection programs.
Did your protection software detect any Trojan or Virus activity prior to the problem? It is possible the protection was incomplete and left a corrupted file or two.
Do you know the approximate date when the problem started? You can look at the files you created on that date, and use that information for a procedure that follows.
Do you have your Browsing favorites and cookies saved? You may wish to create a backup (click FILE, IMPORT AND EXPORT, then follow the instructions).
I will assume you are running Windows 7 since you have IE9, but other versions are similar:
First go to START, then CONTROL PANEL
Change Settings (top right) to LARGE ICONS (to match instructions)
Select PROGRAMS AND FEATURES and a list of installed programs appears.
Now here you have a few options:
First click the heading INSTALLED ON heading, and see if an odd application appears around the date your problems started. Be very suspect of any browser add-ons or search related software. If you find anything questionable, you can do a net search or make a note and uninstall it . . . you should be able to find it on the net later if it needs to be re-installed.
If the problem is gone after the re-boot, you have a fix, if not, continue.
If your computer shipped with IE8, you should have a record of the install of IE9 on the above page. Follow the above instructions and return to the PROGRAMS AND FEATURES selection.
Click on the NAME heading to place installs in alphabetical order, and look for the install of IE9. At that point you can select to uninstall the program.
If your computer shipped with IE9: from the PROGRAMS AND FEATURES page, and in the top left of the page, select TURN WINDOWS FEATURES ON OR OFF, then UNCHECK IE9
After either selection, you will need to reboot your computer.
Now use your Firefox and download a clean copy of IE9:
If the install program requests a repair or complete install, I would suggest complete, but you could spend the time to try a repair.
Once installed, your system will require a re-boot. When opened, IE9 should request authorization as primary browser. Hopefully, if you dont have the Google or Firefox Trojan, and you dont have protection software that locks-in another setting, your system will now accept your browser selection.
Remember, you may need to run Windows Update a few times to bring your new install up to date. In addition, you can import your old IE9 settings from your back-up if they were lost.
Once again, I hope this helps!