Here are the possibilities.
First you need to reseat the ram , gpu , and cmos battery.
Second. If does not work , try to use some eraser to clean out the pins of the gpu and the ram.
Third , give some clean. Remove all the dust from your GPU fans and CPU Fan to avoid high temperatures due to the dust.
If does not work please let me know , and if has a beep codes? Tell the motherboard brand and product id and how many beeps.
Example:
1 short 2 long beeps.