If 2 Firefox installations show in the Windows Control Panel > '''Programs and Features''' it could be for two reasons. 1. being that there is both a '''x86''' (32-bit) version and a 64-bit version that is or ''was'' once installed. <br>''I would search my hard disc to see if '''''2''''' - '''firefox.exe''' files are found, and if so exactly in which folders before un-installing Firefox, to be safe.'' 2. That the Registry key for Firefox wasn't cleaned up after a Firefox newer version was installed; common with Windows before Windows10 came into being. And if you un-installed Firefox now, you might discover as many other users have that there was really one version of Firefox installed and you would lose that one version. But, not a big deal because merely un-installing Firefox doesn't remove the Firefox user Profiles and data that the user has saved. A new, fresh installation should "pickup" the Profiles and all their data without even a "hiccup". Downside, is that if your disc is "that low", you would be better off with a new, larger disc drive. The "user Profile and its files" take up far more disc space than the Firefox installation files use. Could be close to a 10 to 1 ratio, and that was like maybe 5 years ago when I looked into doing a comparison ....