I just replaced my mobo and it didn't beep at post, so I thought the mobo was the problem. However, after trying everything, I got it to work by resetting the cmos/bios. I had to take the battery out, and move the jumper, for 30 seconds. Just moving the jumper did nothing. Try this and see if it helps. Does your motherboard have integrated graphics? If so, take the gpu out, plug your monitor directly into the board, and see if it boots. If it does, it's your GPU.

Also, I did not reformat my hdd or reinstall windows and my pc is running fine.

My mobo still doesn't beep, and never did, not sure why lol.