Need Guru Help with unusual problem: Office 2013 and firefox

Have brand new HW and W7 Paranoia in place about new system and www: behind router, Firewall on, NIS, Malware Bytes and Webroot installed before connecting Firefox installed with standalone offline installer: NoScript, AdBlocker... Installed Office home Premium Subscription Wiith Firefox as default, clicking on Document>File>Account> Mange account button, Firefox opens with extra tab: some add site, for me it is www.69a.com. ( different for others, but similar sites if linked to ) Happens with Chrome too With IE set as default: same sequence: Firefox opens with same extra tab !!?? Uninstall FF and chrome: IE works ok and takes me to Office Account log in. Have scanned till blue in the face with malware tools: nothing seen. Several other users have noted same behaviour: no solutions ??? I have done all the suggestions as noted: no change. See here: https://support.mozilla.org/en-US/questions/1000206 https://support.mozilla.org/en-US/questions/1004509 https://support.mozilla.org/en-US/questions/1004509#answer-586091 and here: https://productforums.google.com/forum/#!topic/chrome/9wuH1qC9fKQ Dont know what's happening Help. Regards