How to change my pirated os to an original one?

my friend installs a pirated OS on my pc weeks ago..........i just bought an original OS yesterday, the big question is, how can i change my OS without the need to reformat it, is there a possible way to load it? it will be difficult for me to start from scratch, thats why i am asking for help, if theres any other way..........How to change my pirated os to an original one?
I respect and admire you for deciding to purchase your own copy.



I would say that because you have a genuine operating system for your computer which you purchased, then you shouldn't worry about the legal ramifications. Unless there's a problem downloading the updates, then it's a technical problem, but not a legal one.



I THINK (but I'm not absolutely certain) that if you boot your computer to the CD you purchased and you begin to install it, there will be an option to repair it. If this option comes up, select it. If this option doesn't show up, then remove the Cd and reboot to your current OS before it gives you the chance to format your hard drive.



If you can NOT repair your OS and you still need to replace it with the one you bought, then your only option is to start from scratch.



If you DO to start from scratch, make sure you first save any documents, pictures, etc, on some thing external to the computer so you can restore it later. (An external hard drive, a USB memory stick, burn it to a blank CD, etc.)



Good luck.How to change my pirated os to an original one?
upgrade to wmp 11. it runs a wga check and when it flags your system, it gives you a chance to buy a legit copy for half price



wmp 11= windows media player 11
You can change your windows key to the legal one. The following article clearly describes how to do this.
Follow the link posted by Joe above, that works as it's only failing based on the current serial number. As long as yours is genuine there will be no problem and no need to reinstall, then windows updates will work fine