I got the solution!
I tried everything first, rebooted, converted MP3 to WAV and AIF, tried different hardware mixes in the preferences, tired the different previews in the Composition menu (audio was ticked but the other other audio options were just a mess), and starting to embark on remapping my keys when I spotted the problem.
The”0″ key to play the RAM preview was beeping when pressed but I found it had already been assigned in the Adobe After Effects 9.0 Shortcuts file… and then it hit me.
You press the “0” key under your numeric keypad!! Ha! So simple.
No need for conversions, MP3, AIF, WAV all work fine. As for the snarky guy who first “answered” this post- go put your head in a bucket. I also went through Adobe’s list and found no joy there…