Description
A few days after I had installed node.js v4.1.1 x64 I installed Visual Studio 2015 (professional), one of the options I selected was 'Joyent Node.js'. Another few days later when I came to installing node.js v4.1.2, the installer program wanted to install in C:\Program Files (x86)... rather than the expected C:\Program Files\ i.e. it was going to try and install to the 32-bit location. I am running Windows 7 Enterprise x64.
My workaround was to uninstall the version of node.js (12.2) that Visual Studio 2015 had installed. After that the 64 bit install of v4.1.2 would select the correct (C:\Program Files...) folder.
I double-checked that the installer I downloaded was the x64 version - it was.
I'm guessing this is something to do with the install of node.js by Visual Studio 2015 that has messed things up and may therefore not be your issue.