WebMatrix Refresh killed the application

I've just updated to the latest Webmatrix Refresh 2 and now Webmatrix won't start. 

Worse, it won't repair, MATS doesn't fix it and uninstalling and re-installing doesn't make it work either.  I've even uninstalled IISExpress, Web Platform Installer and SQLCE.

My event log has several errors including:

Fault bucket 3485074181, type 5
Event Name: CLR20r3
Response: Not available
Cab Id: 0

Problem signature:
P1: webmatrix.exe
P2: 7.1.1692.0
P3: 509e0161
P4: mscorlib
P5: 4.0.30319.18034
P6: 50b5a7a9
P7: 3e10
P8: 4
P9: PSZQOADHX1U5ZAHBHOHGHLDGIY4QIXHX
P10:

Attached files:
C:\Users\Mark11\AppData\Local\Temp\WERE6E6.tmp.WERInternalMetadata.xml

These files may be available here:
C:\Users\Mark11\AppData\Local\Microsoft\Windows\WER\ReportArchive\AppCrash_webmatrix.exe_106242755ce3a149523cff5097bbcd1c122c3176_21a204d2

Analysis symbol:
Rechecking for solution: 0
Report Id: e71979b1-857a-11e2-abde-00241d857a5c
Report Status: 0

and

Faulting application name:WebMatrix.exe, version:7.1.1692.0, time stamp:0x509e0161
Faultingmodule name: KERNELBASE.dll, version:6.1.7601.18015, time stamp:0x50b83c8a
Exception code:0xe0434352
Fault offset:0x0000c41f
Faulting process id:0x16d0
Faulting application start time:0x01ce1987a93fb4ac
Faulting application path: C:\ProgramFiles(x86)\MicrosoftWebMatrix\WebMatrix.exe
Faultingmodule path: C:\Windows\syswow64\KERNELBASE.dll
ReportId: e71979b1-857a-11e2-abde-00241d857a5c

and

Application:WebMatrix.exe
FrameworkVersion: v4.0.30319
Description:The process was terminated due to an unhandled exception.
ExceptionInfo:System.Runtime.InteropServices.COMException
Stack:
   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32,IntPtr)
   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHR(Int32,IntPtr)
   at MS.Win32.UnsafeNativeMethods+HRESULT.Check(Int32)
   at System.Windows.SplashScreen.CreateLayeredWindowFromImgBuffer(IntPtr,Int64,Boolean)
   at System.Windows.SplashScreen.Show(Boolean,Boolean)
   at Microsoft.WebMatrix.Core.WebMatrixShellApplication.Execute(Boolean,Boolean,Boolean,Boolean)
   at Microsoft.WebMatrix.Core.ShellApplicationHelper.Microsoft.WebMatrix.Core.Interop.IShellApplication.Execute(Int32)
   at Microsoft.WebMatrix.Core.ShellApplicationHelper.Execute()
   at Microsoft.WebMatrix.EntryPoint.Main(System.String[])

Any thoughts on how to get it working again?