opening trunk w/ dead battery?

[eddieo45]

just got back from 10 days away, and the C280 appears to have a dead battery (which I had just replaced in February; maybe I need an alternator?). remote won't unlock doors, so I used the mechanical key, and once inside, no lights on dash, and the key won't turn (?) in the ignition. worst of all, the trunk won't open, so I can't try to simply jump the battery. I can push the trunk release in to no avail, and, using the mechanical key, can lock (horizontal) and unlock (vertical, which is how I usually have it) the trunk, but it won't pop open. any ideas?