I also downloaded a 7-day trial version of the abacus.com premier collection concorde, but it didn't show up in the aircraft menu at all...
I just downloaded the Abacus trial Concorde to check it out. It's posted in 2 versions, for FS2000 or FS2002 so make sure you downloaded the correct file (AbacusConcorde_FS2002.exe). This is auto-install so should install itself correctly. The sound.cfg of the FS2002 version is aliased to the default b737_400 so it should work providing you didn't change the folder name of the b737_400 or delete it. The FS2002 Aircraft.cfg entries are missing so it will be listed under Unspecified as manufacturer on the FS2002 selection menu. My guess is that you're looking in the wrong place on the menu.
