Problems with FFmpeg in version 1.3.12 and problem upgrading to version 2.3.3

The error message is most likely to be because your computer’s version of “Microsoft C++ Redistributable” is out of date. You can get it from Microsoft here:

You need the “x86: vc_redist.x86.exe” version (because Audacity is a 32-bit app).

You should consider updating your operating system as Windows 7 is obsolete and no longer supported. If you don’t want Windows 10, you could consider using some version of Linux. (“Xubuntu” is easy to use and is a good choice for older computers)

Because Audacity 1.3.12 is so massively out of date (it has been obsolete for years), I would highly recommend uninstalling it before installing Audacity 2.3.3.
Also, during the installation of Audacity 2.3.3, ensure that the option to “Reset Preferences” is selected.