HOW CAN I STOP POP UIPS ON MY COMPUTER

Are these as small popups on bottom right corner of Firefox window?. If so then these are likely just web push notifications from sites you have allowed to send you notifications. You can revoke the sites as shown in https://support.mozilla.org/en-US/kb/push-notifications-firefox Are these as popups opening in new tabs or new small windows or such while on some websites?. Then perhaps a ad blocker related extension like "uBlock Origin" among others may help. https://addons.mozilla.org/firefox/addon/ublock-origin/ Maybe you changed your popup blocker settings in Firefox. https://support.mozilla.org/en-US/kb/pop-blocker-settings-exceptions-troubleshooting