npm install does nothing - how make it work?

Thetoast found solution that worked for me.

If you have the same problem check the value of your TEMP environment variable. To do so run nodejs' command window and type

echo %TEMP%

You should receive path to a single directory. If you receive multiple directory (as I did - I received C:\Users\<user>\AppData\Local\Temp;c:\Users\<user>\AppData\Local\Atlassian\SourceTree\git_local\bin\) it means that this might by the cause of the problem. You can fix it by typing

SET TEMP=<correct path to temporary directory>

where <correct path to temporary directory> might by the first path (before semicolon, that means C:\Users\<user>\AppData\Local\Temp in my case).

I had some issues with the npm install bower -g aswell but try this command:

npm install bower --global

this one worked for me