Q: if my computer doesn't show 'reset my security questions' what do i do to change my security questions because I can't remember the answers.

That mean that you don't have a verified rescue email address on your account, you will have to contact Support in the country where you are (and which is therefore the country on your account) to get the questions reset : Contact Apple for help with Apple ID account security

If your country isn't on that page then try this form to contact Support : https://www.apple.com/emea/support/itunes/contact.html

When they've been reset you can then add a rescue email address for potential future use : About your Apple ID email addresses - Apple Support

Or if it's available in your country you could change to 2-step verification : Frequently asked questions about two-step verification for Apple ID