What's the message you get?

Did you try to "Run" or "Save"? It's safer when downloading any programs to use "Save".

If the main site download doesn't work, you can try the FTP server here: ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/5.0/win32/en-US/

"Your current secuirty settings will not allow this file to be downloaded". I have IE 8.0 and AOL 9.6 as the browser.

In case this message is generated by malware, you may want to run some supplemental scans. These two tools are highly regarded:

Malwarebytes Anti-malware : http://www.malwarebytes.org/products/malwarebytes_free

SUPERAntiSpyware : http://www.superantispyware.com/

Will your system allow you to download and run either of those?

Thanks.

Another idea based on a web search: make mozilla.com a trusted site in IE. You can do this while viewing the site by double-clicking "Internet" on the status bar. In the security dialog, click Trusted, then the Trusted Sites button, and saving mozilla.com there. When you exit the dialog, the icon on the status bar should change from the world to the green check mark.