Visual studio project properties tab "web" missing

I have recently started having a strange problem with visual studio 20开发者_如何转开发08 sp1: in the properties of my web projects I can't see the Web tab - I get the following error:

Unable to create the designer. File is already opened in an incompatible editor.

Or in the case of ASP.NET MVC:

An error occurred trying to load the page. 909d16b3-c8e8-43d1-a2b8-26ea0d4b6b57

I can see the "web" tab if it's not selected immediately but once i click on it, the header of the tab goes blank and tha main pane just shows the error. I have unistalled both VS2008 and MVC, reistalled - same thing. Tried devenv /resetsettings also... Nothing on google either:( I would really appreciate any help, I'm stuck!

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I begin getting this same error after changing the visual studio "environment > font and colors > environment font" to calibri. Fixed by changing font back.

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Found the solution! When i tried to open IIS, the IIS MMC snap-in crashed with the message "Font 'Segoe UI' does not support style 'Bold'." Changed the windows theme to classic which does not use sagoe ui, and voila - all problems fixed...