Intake fan (3-pin 100mm) stopped working

[ilcul8rk]

The intake fan was working when I first loaded my system, which also houses two smaller rear exhaust fans, but the 100mm front fan is the only thing plugged into the 3-pin on the motherboard. The rear fans are powered by the 4-pin connectors. The front fan stopped working, so I replaced it, but the new fan doesn't work either...is it a motherboard issue or something in the BIOS?

 

[wa1]

More detail needed here, list the rest of your system please...
My front fan has 4pin connector, i never see a 3pin power connector before......