Your message is not very clear:
needed to reactivate but I get new activation menu with browser, etc,..
What's a "new activation menu with browser, etc" ? There's no "new" activation menu. Perhaps you are referring to the OFFLINE activation method ?
This was always available, and it only comes if there's no internet connection available or the activation server cannot be contacted, usually because you have a firewall which is blocking online access to the activation server. In this case, turn off all firewalls and/or allows FSX to go online in the firewall settings.
I went to browser got new activation code , entered new code but activation fails each time.
What do you mean with "fails each time" ? You surely must have you some kind of error message, but it's not very easy to help you just say "fails".
Unless you really don't have an internet connection, if you fix your firewall problem, you can use the normal online activation, which is easier and doesn't use the browser.
If you are unable to fix your firewall problem, the offline activation surely works too, and it's done this way:
http://www.fsdreamteam.com/forum/index.php/topic,11998.msg91498.html#msg91498
