My Acer Aspire 5551's screen suddenly goes black when when using it, I have to turn it off and on again and it's normal upon restart. I had this problem for a number of months and recently when it happened upon restart it just gave me a black screen with a message about operating system error so I took it to be repaired and they told me after diagnosis it wasn't hardware, it was my version of Windows. So they fixed that with new Windows and it's been fine for 3 weeks, then yesterday started doing it again . The added problem is now I've just moved to Moscow so I can't return it to the repair shop!