Email communication is the slowest way of getting anything done Yvonne. Better for you to either phone Customer Service or if that would entail long distance charges use their online chat service linked under Useful Links at the top of this page which will bring you immediate service and is free. Alter your country preference at the top right accordingly if necessary.
That said....Assuming this purchase was from McAfee direct and not some 3rd party, It is compatible with Windows 7 SP1 both x86 or x64. It is also recommended that you upgrade Internet Explorer to version 9 from the native 8 that comes with the system. There may be another technical reason as to why it isn't succeeding such as how you connect to the internet or that your operating system has remnants of another security software. Technical Support is available free by phone or online chat and they would be glad to help you with that. (Email communication is not recommended).
However if you still want your money back Customer Service is the department you need and, as I stated, online chat is possibly your best way of contacting them.