No, I'm afraid Robert won't be your mother's brother straight away. You need to re-install Windows as your first step so you need either an original Windows CD or a Restore CD. One or other of those should have been given to you when you bought the PC. When you find it (or not) come back to us.
Extra memory is always worth having. Do you know what the specification is of your PC, hard disk size, memory, processor etc. If not go to this page and download SIW. That will tell you more things than you thought possible about your PC. Give us a bit of info about the hardware and we'll come back with some ideas.
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Do you know that we're all in line for succession to the throne? Really?
Well, if forty-eight million, two hundred thousand, seven hundred and one people died I'd be Queen.