I tried to install/upgrade to Firefox 26 on this Win XP SP3 computer, with the result that the old FF icons on desktop were changed to folder icons. Clicking these shortcut icons (folders) did not open Firefox. So I thought I might downgrade FF to 18.2 to restore the FF icons, but got the same result. Recently, the executable you download from mozilla.org does not give the full program, but instead you get a program that initiates a full download when you execute it on your computer. This initiator program experienced a fatal interruption every time, so I had to resort to full program downloads. I tried to install several versions of FF going back to as early as FF 12, with the same result, that "firefox.exe" was generated as an empty folder rather than the executable script associated with the FF icon (red globe), which was missing. I tried to change the icon for FF shortcuts, but when I looked in the folder for available icons, the Firefox red globe was missing; in fact, the folder was completely empty, so the installation process does not generate the FF icon at all. After installing FF 26 for the third time, I deleted the "firefox.exe" folder located in 'C:\Program Files\Mozilla Firefox' and then copied the firefox.exe icon/script (red globe) from another similar computer, and thereafter Firefox opened from terminal and also from generated shortcuts. Okay, so I got Firefox to work, but I am concerned that my computer has a fundamental problem if multiple FF installation programs consistently generate this empty folder (named "firefox.exe") where the FF executable should be, and also create folder icons instead of FF icons as shortcuts. Perhaps an extension has been incorrectly associated. Does anyone have an idea why this is happening.