How to solve the problem "macbook keeps waking up"

Here is the problem of my macbook: after closing the lid on the Mac laptop, the machine sleeps. Then if I remove the cable/USB driver etc. from the macbook, it keeps waking up and sleeping. Now:

1. check /Library/Preferences/SystemConfiguration/, I guess there is no file "com.apple.AutoWake.plist' there.
2. System Preferences - Energy Saver - Schedule... - check 'Start up or wake'.
3. Now the file "com.apple.AutoWake.plist'  appears
4. Uncheck 'Start up or wake' in Schedule window.