I was forced recently to re-install Windows 7 after some problems arose thant I could not fix . The laptop is an Acer Extensa 5620 , rather old now but still functioning . After reinstalling ( this time I changed to 64 bit ) it was working very well . Now it keeps going into sleep mode . ODDLY ,It does not do this when playing a DVD ( External USB ) or watching a DVD from the HDD ( internal and external ) , but does several times when playing a game ( not Graphics intensive ) and using the internet through a USB dongle . The Battery has not worked for some years as the price ( robbery )is a quarter of the price of a brand new and better laptop . So I use a UPS , and thought that might have been the problem , but bypassing it still did not sort out the sleep issue . I have tried changing the power plan settings and other changes some advise but still the same issue . Is it an Issue with 64 bit or .net ? Hoping someone can shed some light on this , Thanks in advance .