Sometimes I see a white flashing curser in the top left hand corner, then the white writing on the black screen an then the windows page comes on. Other times I get a small square in the middle of the screen that says "going to sleep" in yellow letters and the monitor light changes to yellow and then the computer power button light changes to yellow also and I have to push the power button to turn it off, nothing else will work. Nothing is loose in the computer. sometimes when I am using the computer and everything seems to be ok, it suddenly freezes. Only the power button will shut it down, there is no reaction to mouse, keyboard, or anything else. This is so frustrating. It is not dependable. Diagnosing the problem is harder than fixing it.