Yesterday my power supply was blown up (fuse). So i bought the power supply (PS HEC 300W) and plug in my compter which is assembly with Intel Desktop Board D845GEBV2 mounted with Celeron 2.0GHz. If i am not wrong, it is compatible with my mother board right. But there is problem after switch it on the power. First i switch on the main switch in the power supply. And i realised that the CPU fan is running although i didn't switch on the power from the front panel of my system unit. The LED for the harddisk in the front pannel also light up even though i didn't connect power to the hard disk. Is it the Mainboard problem.