Download link Design Standard CS 5.0
Please download the trial version of CS5 Design Standard from the below mentioned steps an activate it with the Serial number. I've attached the screenshot for better picture.
Download CS5 products
P.S - If this or any other response helps answer your question, please take a moment to mark the response as helpful or correct to make it easier for future users to find the solution to the same issue.
Let me know if it helps.