Why wont S.T.A.L.K.E.R.: Clear Sky work on windows 7?

i just got a new computer, (just in case you need to know) Acer touch screen with windows 7, intel core processor, intel GMA HD graphics and that's all i know it has, and i just installed stalker clear sky and a 'user account control' window comes up saying 'do you want to allow the program to make the following changes to this computer' so i click on yes then another window comes up saying 'insufficient privileges: you must be administrator when you run this application for the first time' and it has the same results when i click on no, the user im on is already administrator and i've even right clicked the game and pressed 'run as administrator' and that hasn't worked, so what should i do?