Setting the value will force future processes in that space to use the specified .NET runtime, like:

set COMPLUS_Version = v3.5

That would force everything to run in .NET 3.5.

http://www.cookcomputing.com/blog/archives/000597.html

It is not necessary to rebuild NUnit. I discovered that if you add the following to the relevant NUnit application config file you can run a test dll built for .NET 4.0. Under <configuration> add:

<startup>
  <requiredRuntime version="v4.0.20506" />
</startup>

and under <runtime> add:

<loadFromRemoteSources enabled="true" />

http://channel9.msdn.com/posts/jmazner/How-To-Tell-Vistas-UAC-What-Privelege-Level-Your-App-Requires/

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1439749&SiteID=1 (Might work)

#include "stdafx.h"//
includes <tchar.h> #include <windows.h> #include <shobjidl.h> //
ShellLink #include <shlobj.h> // IShellLinkDataList
(build on Vista use shobjidl.h) #include <objbase.h> //
CoInitialize, CoInitializeEx, CoUninitializeint _tmain(int argc,
_TCHAR* argv[]) { HRESULT result; WCHAR wbuf[MAX_PATH]; IShellLink* link; IPersistFile*
file; char szFile[MAX_PATH]; char szProgramMenuFolder[MAX_PATH]; //
SHOULD use CoInitializeEx, but compiler can't find it. result = CoInitialize(NULL); //
For Ex: 2nd param: COINIT_APARTMENTTHREADED// Create IShellLink
object result = CoCreateInstance(CLSID_ShellLink, NULL, CLSCTX_INPROC_SERVER,
IID_IShellLink, (void**)&link); if (result
!= S_OK) { CoUninitialize(); return -1; } //
Retreive the IPersistFile result = link->QueryInterface(IID_IPersistFile,
(void**)&file); if (result
!= S_OK) { link->Release(); CoUninitialize(); return -2;
} // SHOULD get from registry. strcpy(szProgramMenuFolder, "C:\\ProgramData\\Microsoft\\Windows\\Start
Menu\\Programs\\"); // DEBUG strcpy(szFile, szProgramMenuFolder); // SHOULD use your
folder and shortcut name. strcat(szFile, "Program Shortcut Folder\\Shortcut.lnk"); //
Convert the filename MultiByteToWideChar(CP_ACP, 0, szFile, -1, wbuf, sizeof(wbuf)-1); //
Load the link data from the file result = file->Load(wbuf, STGM_READ); if (result
!= S_OK) { file->Release(); link->Release(); CoUninitialize(); return -3;
} // Look for IShellLinkDataList interface IShellLinkDataList*
pdl; result = link->QueryInterface(IID_IShellLinkDataList, (void**)&pdl); if (result
!= S_OK) { file->Release(); link->Release(); CoUninitialize(); return -4; //
Where did IShellLinkDataList go? } DWORD dwFlags = 0; result = pdl->GetFlags(&dwFlags); if (result
!= S_OK) { pdl->Release(); file->Release(); link->Release(); CoUninitialize(); return -5;
} // Only set SLDF_RUNAS_USER if it's not set, otherwise//
SetFlags returns an error.if ((SLDF_RUNAS_USER &
dwFlags) != SLDF_RUNAS_USER) { result = pdl->SetFlags(SLDF_RUNAS_USER | dwFlags); if (result
!= S_OK) { pdl->Release(); file->Release(); link->Release(); CoUninitialize(); return -6;
} } else { pdl->Release(); file->Release(); link->Release();
CoUninitialize(); return 0; } result = file->Save(NULL, true); if (result
!= S_OK) { pdl->Release(); file->Release(); link->Release(); CoUninitialize(); return -8;
} result = file->SaveCompleted(NULL); if (result != S_OK)
{ pdl->Release(); file->Release(); link->Release(); CoUninitialize(); return -9;
} pdl->Release(); file->Release(); link->Release(); CoUninitialize(); return ERROR_SUCCESS;
}