It's over in the CNET Laptop Troubleshooting forum so here's the short version.
Turn off, remove AC, battery then press and hold the power button for 60 seconds. Release, slip in the battery then apply the AC and retest.
My netbook was working fine and was connected wirelessly to the internet. I left it for 5mins and when I came back to it, it had switched itself of. It now will not turn back on and shows no lights when plugged into the mains.