If McAfee displays that your computer is at risk kindly make sure that your operating system is updated. Because McAfee will be depending upon your Operating system.
And the account which displays that your computer is protected is a place where the name of the computer's will be displayed where you have installed McAfee on it.
So dont confuse yourself. You are having a good software installed on your computer. if some thing is going wrong on your computer obviously McAfee will say that your computer is at risk. So check for the issues in your computer and get it done.
To be more clear what is happening on your computer you can call McAfee Technical support 1-866-62-3911.
What software suite are you installing...the name please? Where are you installing it from and if a CD how old is it? It sounds to me more like you are running a sales tool called McAfee Security Scan Plus which isn't an antivirus, merely something to tell you what you need. If that is the case uninstall it in the normal manner and start over with the proper software. MSSP is often bundled with Adobe products so it you have just installed Windows 8 and are updating it it's possible you overlooked the option to uncheck this additional sales tool.
Are you downloading from an online account? Make sure 8 is up to date first, then try.