Resource editor not available in Visual Studio 2008

When I right-click on a resource file in Visual Studio 2008, I get the following message:

There is no editor available for 'D:\MyPath\MyProject\Resources.de.resx'. Make sure the application for the file type (.resx) is installed.

Any idea on how to solve this issue? By now, I am stuck with opening the resource files as XML text.

I am working with Visual Studio 2008 Professional Edition.

Update:

Unfortunately (for me), uninstalling and installing again Visual Studio 2008 Professional Edition and its service pack did not solve the problem.

Incidentally, I cannot see any C# Project Properties page, either. When I try to show them, nothing happens.

Update 2:

I finally solved my problem. I added an own answer explaining how.

Solution

I finally solved my problem. What I did, inspired by this answer to another question, was:

Reinstall Visual Studio - to no success. Looking at it retrospectively, maybe my uninstall wasn't complete - but I really thought I had uninstalled it.
Start Visual Studio in safe mode: from the Windows command prompt (Start|Run...), type devenv /safemode.
At the Project menu, click Properties. A message appeared saying that some relevant package (something like Project Designer) had not been loaded due to previous errors, and I could load it again by starting Visual Studio with devenv /resetskippkgs. After doing so, the project properties are loaded normally. As a consequence, the resources, which belong to these properties, can be viewed.

So, to summarize, I just needed to take advantage of devenv /safemode, after which Visual Studio suggested me to use devenv /resetskippkgs.