I cannot download a working version of Firefox at all. Downloads seem normal but No Program in "Add or Delete programs"and NO ICON

Question

I kept getting a mssg "update did not download. make sure there are no other copys of Firefox on your computer". That was on the user account I use strictly for the internet. I keep 3 user accounts, One is the administrator for security, a sort of 3 card monty for security purposes. The one I use for the internet kept repeating that mssg (I sure do miss the firefox spellcheck. I dont like Internet Explorer at all).
In frustration I deleted firefox from all three user accounts and attempted to download a fresh browser. All things seemed to download as normal but after the restart there was no Firefox Icon or any evidence of the program in the "Add or Delete Programs". It simply seems to disappear.
I tried downloading on the administrator account and the other two to the same effect.
I tried to do over and began to notice on the File Download-Security Warning Dialox Box that there were several different addresses beside "From;" from several different countrys, including halifax which didnt appear in the following examples
For exampl the dialog box I have up now says
File Download-Security Warning
Name: Firefox setup 6.0. exe
Type: Application, 13.3MB
From: mirror.informatik.uni-mannheim.de
Now I am going to delete this one and click the download from Firefox homepage again and it should be another;
It is. Same Dialog Box but
FROM: mirror.team-cymru.org
I delete and do that again...and also a different
FROM: mozilla.mirror.ac.za
try again..and yes it is different too;
FROM: mirror.metrocast.net
try again...the same result
FROM: mirror.Istn.net
try again...
FROM: www.mirrorservice.org
try again...
and for the first time this session I get a repeat of the last result.
My intuition tells me this cant be normal in conjunction with the fact that after going through a normal download process any of these possibilities needs to restart and then after rebooting there is no firefox icon or any evidence the program downloaded at all.
Perhaps I could do a check of the math on remaing MB space, but there has to be something wrong here.

Answer 1

Using "System Restore" can cause your Firefox installation to get corrupted because not all files are restored (only files in a white-list), so be cautious with using System Restore.<br />
You need to (re)install software that was affected.<br />
Remove the Firefox program folder (C:\Program Files\Mozilla Firefox\) before reinstalling a freshly downloaded Firefox copy to do a clean install.
You can find the latest Firefox release in all languages and for all Operating Systems here:
*Firefox 11.0.x: http://www.mozilla.org/en-US/firefox/all.html
Remove all rules for Firefox and the plugin-container from the permissions list in the firewall and let your firewall ask again for permission to get full unrestricted access to internet for Firefox and the plugin-container process and the updater process.
See:
*https://support.mozilla.org/kb/Server+not+found
*https://support.mozilla.org/kb/Firewalls