I'm trying to install the plug-in Sony Noise Reduction 2h to clean up some audio in Vegas. After installing the plug-in does not show up in the list. Any ideas? Is it because I'm using Win7/64bit?

What audio program are you using to trick out your sound? I use Sound Forge. When I have to do an audio cleanup, I right click on the offending audio clip and "open a copy in Sound Forge". The clip opens in Sound Forge and the plug in appears in the tools section. I do the processing, save "take two" and leave Sound Forge. The clip pops back into the timeline.
Hope that helps.

Sony Noise Reducer is a 32-bit plugin and will not work int he 64-bit version of Vegas.