I just installed latest version of node (0.6.12) in Windows 7 using msi (node-v0.6.12.msi).
npm is already shipped with it, no need to include it separately.
I was facing permission issue while running npm (npm install mysql), from the path where my nodejs resided, i.e. C:\Program Files (x86)\nodejs
Then I followed below steps:
1) Added C:\Program Files (x86)\nodejs\npm
in environment variables - Path system variable.
2) went back to only C:\
in command prompt and gave the command - npm install mysql
- and voila! it worked..
Hope this helps.