Build website back end for antivirus SaaS deployment

We are an antivirus product company & want to launch our product via our website. For this we require to build the back end to enable users to download our antivirus from our website. The requirements are 1. Downloading software as per system configuration When user clicks on the download button on our website, a small installer program gets downloaded. This installer program when run by the user will check for operating system version & connect to the server to download the appropriate file for installation & run the installation program(will be provided by us). 2. Auto upgrader to download newer versions from the server The installation package will also install on the client machine an auto upgrader(to be developed by you preferably in C#) which will automatically run at scheduled times & connect with the server to check for newer versions of any files used by our antivirus. If yes then download that file from the server on to the client machine. 3. Back end & Logs Dashboard The back-end should also have a dashboard where we(the company) should be able to upload newer versions of files. It should also be possible to get the detailed logs(fetching Username, IP, version installed, date and time of update/install) of the installations done on client side. 4. User Registration This should be an optional module which we may use in the future that the user has to register to continue using our product.