Hi, i've experienced the following problems recently concerning my Mac Pro Early 2008 A1186 (Apple Mac Pro Quad Core 3.4 Intel Core i7 MacPro3.1 MA970*/A) when i have attempted to switch it on the the led light blink & flashes (hear the fans whirring) but does not boot up since Sunday & Monday 07/12/14 08/12/14, on two separate days consecutively prior to this Mac Pro Early 2008 A1186 shut down and then rebooted (Apple Chime) immediately. Can you give me a rough idea what could be the cause of this particular problem and roughly how much will it cost to put it right? Is it due to the Mac Pros logic board, RAM riser replacement, CPU replacement, HHD replacement, including data transfer, Graphic card replacement, Power supply replacement etc?