Reactivate Windows 7?

Not sure if this is the correct thread but a while ago i had a really bad virus on my Asus G73. We tried so lots of methods to fix the problem but we had to resort to our emergency choice which was to wipe the hardrive clean. My Asus G73 BST7 model didn't come with Windows 7 backup or anything. So i installed a "particular" version of Windows 7 from my friend. Good news was that the virus is gone and my laptop works perfectly. Bad news is that i don't have a genuine version of Windows 7 on. I didn't notice this but at the bottom of the laptop there is a Windows 7 Product Key. I was wondering if I'm able to activate windows using it? and how exactly do i do that?

Also i don't think this happened before but when i slightly squeeze the right side of the laptop when it's closed, it makes a really like creak noise. It's difficult to explain but i took a video of it: Creaking Asus G73.3gp

Thanks.

 

Control Panel -> System -> Activate Windows. Follow the instructions and put in your key.

 

If you use the following link to download a legit copy of win 7 http://forum.notebookreview.com/win...-digitalriver-windows-7-sp1-13-languages.html
and load it you will be able to use the key on the computer but it may require a phone call to M$ to activate.
From the desktop press F1 - search for 'activate windows' for details.

 

I used this: Advanced Tokens Manager - The Activation Backup Solution

It requires you to have an already activated Windows 7 in order to use it properly.

 

I think theres some programs that can check out what your KEYS are for windows if that is your problem, they look through the registry.