How to find the GUID of installed programs

Original Post: Original document: http://elmaskubilay.blogspot.co.nz/2012/06/find-guid-globally-unique-identifier-of.html

From CMD or Powershell:

wmic product list (lists all programs with GUID)
wmic product get (Generates list)
wmic product get > C:\installprogs.txt (Exports the list)