Why is this happening? Out of the blue, the screen goes black and i have to press a button to get the screen to come back to life. Screen saver is set to five minutes, but this happens with no warning while I'm typing etc. Other thing that has started happening concerns the mouse losing connection. Yesterday I got the warning about battery power, so I swapped in new batteries. Ever since, it has been losing the connection for about thirty seconds before re-connecting. What's going on? Machine is about four years old now.