No Display after a long beep sound

Hello,

Hi DJ....just wanna share my situation and hopefully u can advice me on this....my pc suddenly giving a long beep sound when i am in a middle of something and my mouse just wont work anymore...then i reboot...after using for a while it happened again....after a few time...after reboot there no more display on the monitor....already try to unplug the graphic card and memory but still the same....all the fan is working and mainboard have beep sound when i take out the memory card....is it my cpu....becoz i already try replacing all items...GCard, memory card and PSU......i am using acer aspire desktop with dualcore cpu and nvidia gcard....