A CMS or an Asp.net Web Project for a web site to sell Software

If there is already a CMS to take care of this then you are free to suggest it, if the CMS is acceptable you will be asked to modify it and get set up or provide the instructions for setting it up ( We will provide the server with remote desktop admin access ) if you have a website for selling software on the web that is different to the breif below it would be definitely considered. I need a commerce web site to sell a software that is already done, The brief so far for the site is : maybe a little bit of design. a feedback page a download page a home page a puchase page linked to paypal (Followings could be done as part of a separate project:) An exposed webservice to activate the product : a user database a license database