I turned off my surge breakers in my room whilst I was cleaning my window, upon putting them back on and turning on my Enermax Liberty 400w I heard a bang, sort of like the bang you hear when trying to run a uber system on a 300w q-tec. (there was defantly no contact of water to anything electrical) I had to turn the computer on then to see if it still works, well it does work but there was this awful straining noise coming from the power supply, I let it boot up and the noise stopped. Everything seems to work alright, so I tried shutting it down and leaving it, then booting it up a couple of times. No noises this time and all seems to be well, I have just give it a full cpu + psu test on s+m and it passed fine, is it safe to keep using it? could it have just been dust in it? the supply is only 2 weeks old and my rig is nowhere near testing it - Celeron D/AA8XE/X600pro/1 HDD+1 Optical. Also, is it recomended to keep turning the supply of at the back after shutting down as my led keyboard and optical mouse stay on which is annoying when trying to sleep. Thanks for any help.