Firefox System Requirements

• To run Firefox on a computer with Windows 7, Mozilla recommends using a computer with an Intel Pentium 4 processor or faster, at least 512 MB RAM and at least 200 MB of free hard drive space. Firefox may run on less-capable computers, but the performance of the browser may be less than ideal.
  
  

Windows 7 System Requirements

• Windows 7 requires a computer with a 1 GHz processor or faster, at least 1 GB RAM and at least 16 GB of free hard drive space. Because the requirements for Firefox are much lower than the requirements to run Windows 7, any computer that can run Windows 7 should be able to run Firefox without problems.
  
  

Other Compatible Operating Systems

• Windows 7 is not the only operating system that can run Firefox. As of 2011, the most-recent version of the browser is Firefox 4. Firefox 4 supports Windows 2000, XP, Server 2003 and Vista, in addition to Windows 7. Firefox also supports Mac OS X 10.5 and later and Linux. If you have an older computer running Windows 95, 98 or Millennium Edition, your computer cannot run Firefox 4 or 3; download Firefox 2 or another Web browser instead.
  
  

Other Web Browsers

• Firefox is not the only Web browser available as an alternative to Internet Explorer. Other alternative Web browsers include Apple's Safari browser, Google's Chrome browser and Opera. Many browsers work on other operating systems, such as Mac OS X and Linux, as well as mobile phones and other portable devices. Camino is an alternative browser for the Mac.