DWG TrueView has taken over file associations for my dwg and dwt files. For dwts under recommended programs there were two, DWG TrueView Application and AutoCAD Application, so simply switched it to CAD and its fixed.
For dwg files the default is AutoCAD DWG Launcher. AutoCAD Application is not in the list. I select acad.exe under the 2010 Civil 3d folder, and it's still at AutoCAD DWG Launcher and TrueView opens the drawings. How can I fix this? I haven't even used TrueView recently so I'm guessing someone else jumped on my computer at the office.
I believe the DWG launcher should be the primary association. It gets updated for each release and keeps track of all valid autodesk products on your machine. So if you run AutoCAD 2009 and then close it and then double-click a DWG file, it should open it with AutoCAD 2009. Then if you use Civil 3D 2011, the next time you open a DWG file it will use Civil 3D 2011. It should probably prioritize AutoCAD over TrueView even if TrueView was used last but I'm not sure on that.