Complete Noob's Guide to Google ADB Drivers on Windows
This method of installing ADB drivers has never failed me and has worked for any android device I've owned or helped with. It uses the Google USB Drivers for windows and nothing else. Hopefully it gets put to good use.
This guide was created using my HTC One (M8) and Windows 8.1 x64 on a Dell Latitude E6530. Both USB 2.0 and 3.0 ports work just fine.
Apologies for the zip of a pdf. XDA has a rather small (488.3 KB) limit on pdf size.
If I've messed up something let me know and I'll see about fixing it.