My LG Nexus 4 phone wont "open" on my PC.

[AC Question]

I plug my Nexus 4 into the PC and the computer registers a USB Device, but doesn't know its a "phone". when i look at my Printer and Devices it sees the phone but i cant access it. i cant open it to "explore" or do file transfers. when i plug the phone in, it doesn't appear in "My Computer" as a storage device or multimedia device. it charges fine but i need to remove the photos cause my internal storage is getting full.