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 .
Need some more details, is it actually going to sleep mode or just shutting off the screen on you and you think it's going to sleep mode? What exactly happens? Is the battery totally out of the system? If not, try it with the battery out. Did you install all the drivers including chipset and power management?