Visual Studio Config File Editor - Not Formatting

My VS 2008 seems to be acting a bit weird and the solution is eluding me.

The problem is that if I open a config file; app.config or web.config, this looks and behaves as a plain text document.

I have no formatting, no coloring, no intellisense and no collapsible or expandable regions.

I have reset all setting and restored default file associations.

If I go into the setting menu, Text Editor, XML开发者_如何学Go, formatting I see an error "An error occurred loading this property page"

Has any one seen this before and have you go a solution.

Thanks

---

From Choose Toolbox Items: An error occurred loading this property page.

Try running

devenv /setup

/Setup (devenv.exe)