In Expression Blend 2, when you choose to edit a code file or insert an event handler for an event, by default, Visual Studio will be launched. If you have multiple versions of Visual Studio (VS) installed, though, you may find that a different version of VS than the one you intended to open will get launched. The most common case is where you have both VS 2005 and VS 2008 installed, but VS 2005 gets launched by Blend instead of VS 2008.
The fix for this involves editing your registry. From the Run prompt (WinKey + R), type regedit and press enter:
With your Registry Editor now running, navigate to HKEY_CLASSES_ROOT\VisualStudio.DTE.9.0\CLSID. Copy the Value Data from this key:
With that value copied, go to HKEY_CLASSES_ROOT\VisualStudio.DTE\CLSID, and overwrite its existing value with the data you just copied a few seconds.
This change should let Expression Blend know to launch Visual Studio 2008 instead of Visual Studio 2005.
Jeetendra “Jeetu” Kukreja