if i search using google i find a post, load it up, login, and whatever i do i cannot get the 'reply with quote' to appear.

this method seems a workaround while the site search is not working and better than starting a new thread, when there are plenty of replies already. is there a cutoff point when threads are dead?

Cos they get locked after a certain period of time, so they won't be bumped. Good feature. You can still post links to the old thread in your new one though.