Hi Luggster:
I'm sorry for the problems you are experiencing with your computer. I would recommend doing two things:
1. File a counterfeit report at www.howtotell.com in order for us to investigate the person who installed the non-genuine copy of Windows on your machine.
2. The preferred and safest method to install your original Windows software is to backup all the files you need (by CD, USB drive, etc) and reinstall based on the original Microsoft product key you have.
Hope this helps,
-Phil Liu