My laptop has my old email address as my Apple ID - how can I change it?

Do a name change to your current email address. This will affect your Apple ID wherever you are signed in. Note the restrictions in the article.

Apple ID Name Change.        

 What to do after you change your Apple ID or password - Apple Support    I suggest doing this before you change your Apple ID or password.

Reset your Windows device to factory fresh and use the Apple ID you want to have when setting it up.