Log in as Administrator and run the installer there.

More details: installing Firefox

That link is worthless. It is for Firefox 3.6.x, which does not have the broken installer that 5.x has.

This situation is utterly ridiculous, and is why I will not be upgrading to a version of Firefox beyond 3.6.x--if I stick with this browser brand at all. I should not have to log in as Administrator proper to install Firefox 5.x; Google Chrome can install without needing administrator rights, why can't Mozilla fix its browser to do the same? Even more frustrating is that Firefox insists on allowing *only* the Administrator to install the software, as well as to update it, not settling for other accounts with administrator rights.

Firefox is absolute hell for other Windows systems I manage, and I have since removed the blight from the computers and installed Google Chrome, which can be updated without my intervention (i.e. logging in as Administrator proper and updating). Even Internet Explorer is a more suitable choice than Firefox at this point. It is no wonder that even Ubuntu will probably switch to Chrome rather than stay with Firefox in the next major version.

Some people may make excuses that Mozilla is not Google, and Firefox is not Chrome. Well, then perhaps Firefox's days are numbered, or it will simply need to be evolved into a browser that is worthy of use. Mozilla needs to abandon the taint of Netscape's archaic profile system, as well as all the other vestigial crap that the defunct company imposed on its browser. This is not 2001; Firefox needs to be fundamentally fixed or it will be abandoned.

Installer URL: ftp://releases.mozilla.org/pub/mozilla.org/firefox/releases/5.0/win32/en-US/

Same as at http://getfirefox.com/ , but this last link will always have the latest version.

Ahh...perhaps that's the problem..I've been using my account, which has administrator rights to install FireFox. Problem is, That's the only account there is. I guess I have to create an administrator user so I can install this? This is pretty annoying. I used to really like FireFox until it got compromised. I also can't run Silverlight so Netflix doesn't work on FireFox. Plugins constantly break or need updating. I think I'm gonna stick with Chrome.

You can install Firefox with any administrator account. You just need to log in instead of using the "Run as ..." feature.

I always log in with an administrator account, and yet it still won't let me install it using it. Not even providing the login info for this admin account will do it. The broken installer insists on the Administrator, and nothing less will suffice. If I'm forced to install this program and its updates using the Administrator proper account, this program's security model is a bit too flawed for my tastes.

I tried creating another administrator account with the name Administrator but it failed saying an account with the same name already exists. Although i can't find this account. Pl help

Hey guys i have solved it!! Just right click the installation file and click run as administrator. It will install properly

<right-click> Run as Administrator

worked for me.

The installer obviously has a major flaw that it does not work like every other program installer. I just got finished installing about 50 programs on a new laptop and all of them worked perfectly except Firefox. Fail.

Thanks for that, mate. The installer is bloody stupid for not working as every other one does. No-one else was intelligent enough to suggest such a simple solution.