For some reason every time I try to run 2.12.2 Windows Explorer goes to (Not Responding)
Uh, do you mean 2.12.0? In any event, if you choose certain options, the installer will need to call the mod tools - which are separate .exes - to compile your chosen mod options, and if you select custom breast size or jiggle mods, the installer will open Instruction.txt files using whatever .txt editor your operating system has defined to be the preferred default - be it notepad, notepad++, or something else.
If your system is having problems with the installer, try to make sure it is not being overzealously blocked by antivirus/security software - since the installer never needs to connect to the Internet you can block it in your firewall if you want, but it does need to be able to call external programs to automatically finalize the install process.
If you are curious what the installer is doing exactly, then when the installer finishes, don't close it just yet, but open your Localdata/bin folder and you may see some .bat files depending on the mod options you chose. These .bat files are called by the installer to compile the mod .bins using the gibbed mod tools or to open instruction text files but then deleted after the installer is closed in order to reduce mod footprint and avoid confusing non-advanced users; feel free to view them to see the exact commands used.
If all else fails, you can of course use the manual install package and install the mods yourself.