I hope one of you guys can make some sense of this cos at the moment it beats me. I had an E-machines pc that would not boot up and the only way to switch power on and off was with the power supply switch at the wall socket. I checked the PSU which seemed Ok and also disconnected the front switch from the mono but still it would only switch on and off at the wall. At this point I assumed it was the mobo that was faulty. Changed the mobo for a MSI board, switched on the pc (from the switch on the pc) and it booted through the BIOS partly into windows but then rebooted.....no suprise as it was Windows XP and a new mobo. I put the windows cd in and started the machine up again, it got part way through boot up and froze and switched off. I rebooted the machine but now it wouldn't boot up again and front switch again not working. There was a slight smell of burning and a strange crackling sound from the southbridge chip (I think) so I assumed the board had failed. I have just replaced the board again, this time with a Gigabyte board and a similar thing has happened, it started to boot up with the windows disc in , froze and now won't boot up, no BIOS at all on the screen. I have tried different memory, a new PSU and a new processor but still no success. The memory and processor came out of another pc that was working fine. Its a socket 478 board and has a celeron 2.6 processor in it. Has anyone any suggestions?? PLEASE!!!!!!!!!!!!!!!!!