Mb have power but not start...

Hi, good day sir, there are several things you should do first.
1. Disconnect all connections to the motherboard.
2. make sure that your Power Supply 4pin 12volt molex and 24 pin molex connectors are tightly plug.
3. Clean the memory port from any dust, plug the RAM module, make sure also the module connector is clean.
4. Plug in the speaker and power switch.
5. Connect a VGA monitor.
6. Reset bios/cmos or simply operate the pc without the battery.
7. Plug the Power Supply to AC mains.
8. test the PC.
9. do this several times if you cant start the PC.
10. if every thing is OK, reconnect your PC and peripherals one at a time.
Hope this helps.keep me inform about your progress. thanks