Generally, if the glass needs to
be replaced in an Andersen product,
you'll need to replace the entire
sash or entire door panel
with a genuine Andersen replacement
part.
Sounds like the balancers are not
functioning properly. The
balancer is usually a spring type
mechanism that counteracts the
weight of the sash when opening.
Probably a seal failure, if the
culprit is in between the glass.
The only cure for that symptom would
be to
replace the glass. Sometimes
that entails replacing the entire
sash or panel.
Not by a long shot. Compare
specs, warrantees and references
when making this big decision.
HandyWorx has comparative
information on most manufacturer's
window products.