So on my laptop (it's an Acer 5552), that has Windows XP Service Pack 3 installed on it, I am encountering this strange bug when I select the "Shut Down" button. The dialog that appears that asks me to select one of the following options (Hibernate, Shut Down, Standby, et cetera) does not appear at random times when I choose it. I can select it one time, and the screen fades, and the box comes and asks me to select whatever will appear at times (which is normal). But most of the time the screen just freezes and I can't select anything, programs, whatever. But when I hit control alt delete it kinda works again, but the gui dissapears ( the start menu, taskbar). And then I have to hit the power button on my computer (which is set to shut the computer down when I press it) works perfectly, it says "windows is shutting down" and then turns off as per usual. I apologize if this is too long winded, and makes little sense. I am not good at explaining things, but hopefully you can make something out of this. I can supply a dxdiag dump if necessary.
