about an hour ago my computer froze on me, I switched it off and re-started it again, all that can up was a black screen, but you could tell that it was on, (its hard to explain) it was making the normal noises but the start up screen wont appear! i really haven't got a clue what to do and i am beginning to panic as this really isn't the week I need this to happen! i will appreciate any advice, thank you xx