i want to de-authorize my pc again before 1 year; i already reset my computer few months before

Howdy ibizhere,

Thanks for using the Apple Support Communities.

To deauthorize the computer you have, all you need to do is follow the directions in the article below.

Deauthorize one computer

1. Open iTunes on the computer you want to deauthorize.
2. Mac: From the menu bar at the top of your computer screen, choose Store > Deauthorize This Computer.
   Windows: Press the Control and B keys on your keyboard to open the iTunes menu bar. Then choose Store > Deauthorize This Computer. Learn more about menus in iTunes for Windows.
   In earlier versions of iTunes, you can access this option from the Advanced menu.
   
3. When prompted, enter your Apple ID and password.
4. Click Deauthorize.

Windows users

If you didn’t deauthorize your computer before you re-installed Windows or upgraded your RAM, hard disk, or other system components, your computer might be using multiple authorizations. Try to deauthorize your computer a few times until it’s no longer authorized, then authorize your computer again. After you do this, it will use only one authorization.

Deauthorize your computer using iTunes - Apple Support

Take care,

Alex H.