vs2010 express for wp7 xaml 无法打开？该怎么解决

vs2010 express for wp7 xaml 无法打开？
无法查看 xaml，也看不到界面的编辑器是怎么回事？
界面编辑器的部分总是提示:
System.InvalidProgramException
Common Language Runtime detected an invalid program.
  at System.ComponentModel.TypeConverterAttribute..ctor(Type type)
  at MS.Internal.Metadata.IntrinsicMetadata.AddTypeConverterAttributes()
  at MS.Internal.Metadata.IntrinsicMetadata.get_CustomAttributes()
  at Microsoft.Windows.Design.Platform.SilverlightMetadataContext..ctor()
  at Microsoft.Windows.Design.Platform.SilverlightMetadataContext..ctor(DesignerPlatform platformFactory, Platform blendPlatform)
  at MS.Internal.Platform.SilverlightPlatformImpl.get_MetadataContext()
  at MS.Internal.Platform.SlmPlatformImpl.get_MetadataContext()
  at MS.Internal.Package.VSIsolationProviderService.RemoteReferenceProxy.EnsurePlatformInitialized()
  at MS.Internal.Package.VSIsolationProviderService.RemoteReferenceProxy.EnsurePlatformInitialized()
  at MS.Internal.Package.VSIsolationProviderService.CreateIsolationProvider(String originalIdentifier, Boolean isGlobal, String identity, FrameworkName frameworkName, AssemblyName appAssemblyName, IVsHierarchy hierarchy)
  at MS.Internal.Package.VSIsolationProviderService.CreateIsolationProviderWorker(String identifier, IServiceProvider provider)
  at MS.Internal.Package.VSIsolationProviderService.CreateIsolationProvider(String identifier, IServiceProvider provider)
  at MS.Internal.Providers.VSDesignerContext.CreateIsolationProvider(IServiceProvider provider, IVsHierarchy hierarchy)
  at MS.Internal.Providers.VSDesignerContext.<>c__DisplayClass1.<Initialize>b__0(IsolationProviderProxy i)
  at MS.Internal.Providers.IsolationProviderProxy.get_RealProvider()
  at MS.Internal.Providers.IsolationProviderProxy.add_UnhandledException(UnhandledExceptionEventHandler value)
  at MS.Internal.Designer.DesignerPane.LoadDesignerView()



------解决方案--------------------
这个XAML是WP7项目生成的么？还是一个普通的SL项目？
如果楼主打开的是一个早期Beta版本的DTK创建的项目，也可能会导致错误。
楼主的工具，创建一个简单的项目有问题么？没问题的话应该就是上述的情况。
------解决方案--------------------
重装也不行？那试试，7.1的SDK?