Starting Yesterday,my laptop has been freezing after 10-40 minutes of operation. This happens no matter if i am using it,or it is just sitting idle.When it freezes,the Harddrive activity light goes out,and all i can do is move the mouse cursor,however clicking anything freezes this also,and the only option is to power down by holding the power button (obviously,not something preferable) Origionally i believed it was a problem with the HDD,and once when it froze A blue screen appeared with the error 'kernel_data_inpage_error ' and on starting up again i got the message 'no bootable media found'. I ran a diagnostic and it said there was no harddrive,yet on another reboot it started up fine,untill it froze ~ 15 minutes later. However,this morning i decided to start the laptop up without using the AC supply and only battery power,and it operated perfectly for over an hour while being used,but unfortunatly froze within 10 minutes of being reconnected to the AC supply. Could the supply be the cause of the freezing? It is a Dell inspiron 1525,INTEL CORE 2 DUO T7500,2GB RAM,Running 32bit Windows Vista SP2. Any help would be much appreciated.