reply to nu2this
Re: delete all prefs... result? If you are worried about some corruption in your Preferences files, it would be better to use a good utility such as MacPilot, Cocktail or Mountain Lion Cache Cleaner - or the free Onyx to scan your preferences and look for problems.
If you toss them all out you will be a very busy boy! You'll have to reset all the preferences for all apps, preference panes, etc. and you will have to remember every password for every commercial product you have ever purchased on your Mac. Not fun!
Rogers (Ericcson) Rocket Hub, Apple Intel iMac, OSX 10.6