Occasionally, I'll be doing something on my computer and it'll suddenly flash a white screen, or sometimes a white screen with vertical lines on it, then go straight back to how it was. Other times, a blank white screen will appear overtop of what I was doing, and will not go away unless I restart my computer. Thing is, I am not doing anything I haven't used this computer for before, and the problem has only started recently. It doesn't occur very often, but it's starting to become more of an issue. My computer is an Acer labtop with Windows Vista installed. Can't say I'm very knowledgeable, so please be patient. ^^;;