My sister has asked me to look at her pc due to "the loud whirring noise" that emanates from it. On inspection, the cpu fan had fallen off and the front tower usb wires had come away from the mobo.The pc had been working but she stopped using it due to the noise. I have simply reconnected the cpu fan but left the usb wire due to not knowing which part it attached to.The pc turns on ok and everything is quiet, but nothing appears on the monitor, no bsd etc.I cant see that there is anything else disconnected, any thoughts? I can hear the hdd spinning away and the re-attached fan spins merrily.The mobo is a msi k9vgm, not sure about the cpu except its an athlon x2, the gfx is an ati, but no idea what spec, any thoughts on what the problem may be?