Out-of-date drivers and operating systems can cause a variety of issues, and are one of the first things to check when a game is having problems.
Troubleshooting steps for disconnections in StarCraft II
Troubleshooting steps for connection problems
What to do if you can't claim a beta key for a Blizzard game.
Troubleshooting steps for latency problems in StarCraft II
How to obtain error logs for Blizzard games
Troubleshooting steps for performance-related problems.
If you have issues with the sound in your game, such as skipping, popping, screeching, or no sounds at all, follow the steps below to troubleshoot the problem.
Troubleshooting for problems installing or patching the Starcraft II game client
Information on moving Blizzard games to a different hard drive