hello sir/mam im starting to having problem when i update my laptop for windows 8 to windows 8.1, i already search the net but cant find the proper solution to it, i will be very thankful if some one could help me..the problem is i cant access my startup menu the windows logo and cant access the charms, if i click the app store it says class not registered and also i cant access some of my settings for example i i want to access my personalize theres a pop up error- explorer. exe- no mapping between account names and security IDs was done..thank you for your time and help