I had to reinstall once again for some reasons and right now I don't have any restart problem.
The issue of Shutdown still hangs in there.

The sound is a major PITA. The last VoodooHDA (2.7.2) does the job splendid but the audio device is not recognised in System Profiler - Audio (Built In). I guess that's the main reason any applications requiring mic input doesn't work. Please, a solution!?

The WIFI this time was solved removing the preexisting IO80211Family.kext and put in place the one provided at the K50IN post.

Please, I need your help?!