stryped,
Then I would think the logical questions to ask are;
Was the replacement battery any good?
How long ago was this replacement done?
Was the battery replaced correctly?

If the answers are that the battery really was good, and it hasn't
been an unreasonable period of time since replacement, and if the
battery was replaced correctly, then it would seem that there is
something else wrong. If you can't find the problem, send it back
to the manufacturor, let them find it.
'Doc