Shutting down 2009 MacBook Pro with new install of 10.7.5, results in restarting?
Based off the replies in the comments, this is what I suggest doing:
In terminal, type the following command:

cd /Library/Preferences/SystemConfiguration/
sudo rm com.apple.PowerManagement.plist
sudo rm com.apple.AutoWake.plist

(Do the &quot;rm&quot; commands separately). Note: com.apple.AutoWake.plist might not exist. Then, shut down your mac, if it re-starts, just shut it down again and hopefully everything will be ok.
I hope this works.
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