Booting Mountain Lion in 32-Bit Mode There are certain applications I use that required me to boot in 32-bit mode in OS X 10.7 (Lion). I could do this by holding down the "2" and "3" keys upon startup. This no longer works since I have upgraded to OS X 10.8.

Is there still a way I can force Mountain Lion to boot in 32-bit mode?
No,
Mountain Lion only boots using a 64-bit kernel which does not support loading 32-bit kernel extensions.
via Arstechnica