I cleaned my PC of dust, reassembled it nice and knit and for the past 48h i've been trying to troubleshoot it. Changed the PSU, the same thing happened. I cannot access the bios without a keyboard. Took out the cmos battery. The only thing i havem' tried is to connect a ps2 keyboard, i've been looking for the adaptor usb2ps2 but no luck. Tried with the mobo out, maybe it wa shorting somewhere, still no luck. Any suggestions?