The latest version of FireFox is version 12. When you install FireFox, make sure that you do not import anything from IE. It will prompt, so read the prompts in the installer. When you install FireFox, I would recommend installing the addon, AdBlock+. There are other security addons, but at a minimum ABP is one you should definately consider.
As others have suggested I would recommend clearing your cookies and Internet History.
Another thing that I would recommend doing is flushing you DNS cache. The procedure is slightly different depending on your OS.
If you are running Windows Vista or Windows 7, do the following.
1. Close any open browser sessions.
2. Click on the start button, and in the search box, type cmd
3. When the cmd.exe program is displayed, right click on it and select the "run as Administrator" option.
4. Click OK if there is a warning prompt about allow this program to make changes to this computer.
5. When the cmd prompt opens, type ipconfig /flushdns
6. Hit enter.
7. You will receive a message that the dns cache server has been cleared.
8. Close the cmd prompt.
9. Open your browser and ensure that you have cleared your history and all cookies.
10. close the browser window
11. Open your browser and see if the issue is resolved.
In Windows XP, just type cmd in the run dialog box. Follow steps 5-11.
If this does not clear up the issue, you may have a poisoned Host file. PM and I will write up a procedure to help you with cleaning it.
There is a possibility that you have a virus or malware. MSE or Microsoft Security Essential is an excellent free antivirus software. I would also recommend installing MalwareBytes AntiMalware. It is an EXCELLENT free antispyware program which runs along side your antivirus program. The paid version offers additional benefits and is often on sale at amazon or Newegg.com. You can get by with the free version though.
Any questions, just PM me.
