"I do keep on getting a message saying that my Windows 7 is not genuine"
Sorry to hear this, sconedd. Unfortunately, there are cowboys in all trades and services these days who are only too willing to rip off the unwary. Do you have any old Windows OS disks? If so you may be able to install an OS using this. If not, you may be able to pick up an XP disk quite cheaply. Do an online search for the best deals.