Dears , DP members . i would like to ask some question to all of you , in here . why my photoshop CS 4 extend . stop working ? he said that your serial number has been expired . i check so many serial numbers on the internet they are not match . anybody in here can solve it ? from now , i used photoshop cs5 portable , is that anybody now . what are the disadvantages of this "portable" product ? thanks ,