A little more information might help, computer type, hardware, recent changes made,if any, software/hardware. Also, what type of security software being used. Does the same situation occur running in Safe Mode? As mentioned, a bit more info might help.
I have tried startup repair, but get the message that it is unable to effect repairs. I turn the computer on after sitting all night and it freezes. I turn it off and then turn it back on and it loads correctly. It seems to happen when the computer has been off for a considerable amount of time. I am using win 7 32 bit.