Windows 7: "Handle invalid" error message.

i am running windows 7 ultimate and last two days i have been getting this error message whenever i try to open a program.for example when i double click on explorer it will not open and i get the error message "This handle is invalid"?
this happens even when i click start button and try to shut down or restart the laptop it says i do not have permission to use this function.i am the only person setup on the laptop and my account is an administrator account.
i have run cmd line "scannow" and that repaired some corrupt files but still problem remains.webroot is not turning up anything and neither is malwarebytes.i have to do a hard shutdown each time i get this problem(power down using on/off switch) and sometimes this works and i can get into explorer,then when i exit explorer and try to get back in again same error message pops up.
please can anyone point me in the right direction as to what might be wrong? i have searched here and googled the message but nothing specific to my access problems popped up