I bought a new computer of core i5 and with geforce gt 620 gpu support. I installed Windows 8.1 on it. However I can't play the game I used to play on Windows 7 anymore. I installed Windows 7 on a dual core processor with less ram than that of the current computer. Things were just fine. All the graphics and animation were smooth. They became laggy only when I opened and viewed many game windows at the same time. Now the game window on the new machine loses its borders, top menu bar and it always sticks to the top left corner of my monitor screen. ..I can't move it down. It is fixed up there. The game screen becomes like being laggy with an incorrect coloring scheme being used. Things occur with only one window opened. Sometimes I see dark blocks of pixels and the colors drawn aren't smooth. My monitor is of LG22EA53, Resolution is 1920 x1080. I also installed its driver on my machine. Would you please offer me some advice or ideas as to why I run into something like that ?I am thinking better machines should offer better effects. . Thank you a lot.