I have an Asus Nexus 7 tablet, and was trying to connecting it in MTP (Media Transfer Protocol) mode to my Samsung Series 5 laptop running Windows 7 SP1 Home Premium Edition. I have a bunch of Android development tools installed also, and typically have my devices connected using the ADB (Android Debug Bridge) driver.
When I first attempted to connect my Nexus 7 to my laptop to use in MTP mode, it simply refused to show up in Windows Explorer. Finally, I figured out that I had to uninstall the ADB device ("Android Phone") from Device Manager and then it would work correctly in MTP mode.
Any ideas why this is? Is MTP mode trumped by the ADB USB Driver?
Note: I always had USB Debugging disabled on the Nexus 7, so it wasn't that.