00 Buick Regal LSE will not start please help

:banghead: Okay my 2000 Buick Regal has full power "new battery" and when i turn the key my dash lights go off along with a little click from under my dash. no noise from the starter or anything. The key was locked in the ignition over night and in the morning she wouldn't start, the battery was almost dead. The battery was changed and connections cleaned. any help would be greatly appreciated :) thanks