I have recently purchased an Acer Veriton X275 with Windows 7 Professional and I am experiencing a nuisance issue. The screen background changes from near white to grey either, after a time lapse or on depression of keyboard key. This can be temporarily rectified by switching the monitor off and then on and, occasionally, by depressing Ctrl/Alt/Del, entering Task Manager and then cancelling. It seems as though a screen energy saver is operating but I am unable to locate it to extend the period before it cuts in. Please advise on this matter.