My computer turn on but no dissplay on monitot please help me i tried erything .thanks

If you already checked the connections, check with another monitor or check with another computer with your monitor. If the monitor is fine, this can be a video card issue, a motherboard issue or power supply issue. Check over the motherboard for bad capacitors, if any are puffy or have stuff coming out of them, you need a new motherboard. If the motherboard looks OK, try to reset the BIOS with the jumper, if that does not help, try a new power supply.