You can make a program to simulate winkey being pressed.
WinKey+R.VB
Imports System.Runtime.InteropServices
Imports System.Windows.Forms
Public Module SendWinKey
Const KEYEVENTF_KEYDOWN As Integer = &H0
Const KEYEVENTF_KEYUP As Integer = &H2
Declare Sub keybd_event Lib "User32" (ByVal bVk As Byte, ByVal bScan As Byte, ByVal dwFlags As UInteger, ByVal dwExtraInfo As UInteger)
Public Sub Main()
keybd_event(CByte(Keys.LWin), 0, KEYEVENTF_KEYDOWN, 0) 'press the left Win key down
keybd_event(CByte(Keys.R), 0, KEYEVENTF_KEYDOWN, 0) 'press the R key down
keybd_event(CByte(Keys.R), 0, KEYEVENTF_KEYUP, 0) 'release the R key
keybd_event(CByte(Keys.LWin), 0, KEYEVENTF_KEYUP, 0) 'release the left Win key
End Sub
End Module
Place on your desktop.
Open a command prompt and type
C:\Windows\Microsoft.NET\Framework\v4.0.30319\vbc "%userprofile%\desktop\Win+R.vb" /out:"%userprofile%\Desktop\Win+R.exe" /target:winexe
A file called Win+R.exe will appear on your desktop. Move it anywhere into the path.