What to do if you can't open the Battle.net desktop app, and there are no error messages when you try.
Troubleshooting steps for latency problems in Diablo III
Troubleshooting issues with sending and receiving new Battle.net friend requests
Troubleshooting issues with 7.zip download and installation
Restoration requests for dead Hardcore heroes in D3/RoS.
Troubleshooting steps for performance-related problems.
Instructions for troubleshooting your network to allow Blizzard services to work properly.