As far as I know the answer is no, I take it you never got an OS disc with the computer?
Normally computers which come with the OS installed and come with no OS disc normally have a restore to factor option if that helps you. Like with a Dell you press ctrl and F11 on start-up.
I'm afraid it sounds like you've got an OEM version installed on your machine i.e. whoever you bought the machine from has the licence to install the software on the machines that they sell.
In this case you would have a restore disk or restore function (that would allow you to create a backup disk) with the machine.