Added code to check version of .Net is 4.5.

Author: Ross Knudsen

Installer Build Script.iss

@@ -122,12 +122,66 @@ begin
   Result := (not Is64BitOfficeInstalled());
 end;
 
+// http://kynosarges.org/DotNetVersion.html
+function IsDotNetDetected(version: string; service: cardinal): boolean;
+// Indicates whether the specified version and service pack of the .NET Framework is installed.
+//
+// version -- Specify one of these strings for the required .NET Framework version:
+//    'v1.1.4322'     .NET Framework 1.1
+//    'v2.0.50727'    .NET Framework 2.0
+//    'v3.0'          .NET Framework 3.0
+//    'v3.5'          .NET Framework 3.5
+//    'v4\Client'     .NET Framework 4.0 Client Profile
+//    'v4\Full'       .NET Framework 4.0 Full Installation
+//    'v4.5'          .NET Framework 4.5
+//
+// service -- Specify any non-negative integer for the required service pack level:
+//    0               No service packs required
+//    1, 2, etc.      Service pack 1, 2, etc. required
+var
+    key: string;
+    install, release, serviceCount: cardinal;
+    check45, success: boolean;
+begin
+    // .NET 4.5 installs as update to .NET 4.0 Full
+    if version = 'v4.5' then begin
+        version := 'v4\Full';
+        check45 := true;
+    end else
+        check45 := false;
+
+    // installation key group for all .NET versions
+    key := 'SOFTWARE\Microsoft\NET Framework Setup\NDP\' + version;
+
+    // .NET 3.0 uses value InstallSuccess in subkey Setup
+    if Pos('v3.0', version) = 1 then begin
+        success := RegQueryDWordValue(HKLM, key + '\Setup', 'InstallSuccess', install);
+    end else begin
+        success := RegQueryDWordValue(HKLM, key, 'Install', install);
+    end;
+
+    // .NET 4.0/4.5 uses value Servicing instead of SP
+    if Pos('v4', version) = 1 then begin
+        success := success and RegQueryDWordValue(HKLM, key, 'Servicing', serviceCount);
+    end else begin
+        success := success and RegQueryDWordValue(HKLM, key, 'SP', serviceCount);
+    end;
+
+    // .NET 4.5 uses additional value Release
+    if check45 then begin
+        success := success and RegQueryDWordValue(HKLM, key, 'Release', release);
+        success := success and (release >= 378389);
+    end;
+
+    result := success and (install = 1) and (serviceCount >= service);
+end;
+
 function InitializeSetup(): Boolean;
 var
    iErrorCode: Integer;
 begin
-  // MS .NET Framework 4.0 must be installed for this application to work.
-  if Not RegKeyExists(HKLM, 'SOFTWARE\Microsoft\.NETFramework\v4.0.30319') then
+  // MS .NET Framework 4.5 must be installed for this application to work.
+  if not IsDotNetDetected('v4.5', 0) then
   begin
     MsgBox(ExpandConstant('{cm:NETFramework40NotInstalled}'), mbCriticalError, mb_Ok);
     ShellExec('open', 'http://msdn.microsoft.com/en-us/netframework/aa731542', '', '', SW_SHOW, ewNoWait, iErrorCode)