Cant start npm on Windows 8 (Error: ENOENT, stat 'C:\Users\User\AppData\Roaming\npm')

I just installed Nodejs on my new computer with Windows 8. I can't get npm to work on it. Although the node server starts fine:

Here's the error:

C:\Users\User\Documents\Source\Project>npm install 
Error: ENOENT, stat 'C:\Users\User\AppData\Roaming\npm'


C:\Users\User\Documents\Source\Project>npm start
Error: ENOENT, stat 'C:\Users\User\AppData\Roaming\npm'


C:\Users\User\Documents\Source\Project>