Redeeming an Adobe CS5 Master Collection key is really simple, just follow these steps:
Download both the links and then run .exe file to proceed with the installation and then activate the product using the serial number for the product.
For English Language Use these links:
For Other Languages Use these links:
The key is not working
If you have activated the key according to the guide but the code appears not to work, please check what type of error message you receive and depending on it follow the appropriate instructions: