You have to turn on the computer first.
Stop using a computer from 2001.
If Regulith's suggestion doesn't work, call the Aperture Science Computer-Aided Enrichment Center. The number is on the back of the box. If your one of the first 20 callers, you'll recieve cake!
Take out the hard drive and put it to your ear; you will hear 'Still Alive' as you slowly fade into a daze. Then, driving the disk ever-so slowly into your brain, not by your command, but by some un-earthly power, you will have visions of the compainion cube as you slowly drift away from your body and reality...
He's probably not responding because he deleted his computer.
How2do?
Don't listen to them. You have to find your system32 folder, and delete it. It'll make the computer faster, which will make the game work.
Well I think his computer would be on if he's posting this.