I got a nice and pretty much unused desktop Lenovo ThinkCentre, made in 2007 (I think). The only thing is, when I connect the power plug into the PC it boots up for a few seconds (fans spinning etc.) then stops (turns off). Then, if I boot it up (turn it on) it starts and works normally. I checked all the BIOS (wake on... etc.) settings, even replaced the power supply - but the problem persists: whenever I plug in the power chord the PC starts for a few seconds by itself.
Any ideas, anyone?