Got Windows 8.1 installed? MTP doesn't work?
Well - maybe you got the Windows 8.1 N Version installed. The Version without Windows Media Player - and without MTP Drivers!
Just install the Windows Media Feature Pack for Windows 8.1 - reboot - and it works. It's Magic, ain't it?!
Searching and trying for about 2 hours to get my Nexus7 to connect with Windows 8.1. Others recommended to install various drivers and or do other workarounds. Nothing worked. Your post saved my evening! Thank you for the solution.
Thanks a lot for writing back - Glad I could be of help :)!