I have coolermaster n300 dont know why i bought but only what i could afford.Cant fit intake fans infront of the case the holes on the case is too small for the big screws.now i have a side panel fan on the back side of the mobo and two fans on top and one at back.how should they be placed can i put two top ones as intake cause room gets very dirty and side fan when it was intake got very dirty.Please help?