I am helping a friend who is haing problems with a Dell Inspiron 9400 laptop computer. When I got it, Windows would not boot and the numlock and caps light would blink for about 20 seconds followed by the computer turning itself off. I did find ino that pointed to a memory problem. I replaced the memory and Windows will boot now. My concern now is this. When I powered the computer on, I turned it over and noticed there is a grid on that covers a fan that does not turn. I believe that it is the CPU fan. If I blow canned air into the opening, the fan does rotate. Should this fan run any time the computer is on or should it run only as needed? Was this the cause of the memory failure? If the fan should run continuously, what could be wrong with it since I can rotate it manually?