Nexus 4 shows up empty on Windows Explorer

[AC Question]

I connected my Nexus 4 to my PC via USB.

When I open the device in Windows Explorer, though, it's empty.

I made sure to install an MTP driver.

How can I access the file system of my phone?

 

[B. Diddy]

Welcome to Android Central! First, the Nexus 4's screen is unlocked, right? If it's not unlocked, the computer won't be able to read it.

Second, swipe down the notification panel and tap the USB icon. Is MTP selected?