My truck will not start, dash lights up, but nothing happens

My 2004 trailblazer has never have me any problems until now. The truck was running fine until we got in it Friday morning to take the kids to school. I got in the truck Friday morning, turned the key, only for the truck to not respond. The overhead lights didn't come on which also was odd, so I thought maybe the battery was dead because the voltage meter in the dash wouldn't move away from the 9 volt mark. I tried to jump the vehicle, nothing seemed to work, I then tested the battery to find that it was working properly. Next I tested all the fuses under the hood and under the back seat, all fuses were operating as they should. Next, I took the steering console apart, to test the signal from the key switch, everything was working, even the start position was sending the signal to start the vehicle, however the vehicle wouldn't respond. Now I turned the key to the on position, and started the vehicle by jumping the solenoid, the truck started only to stop running almost immediately. When you turn the key on, you can hear the dual pump turn on briefly, to pressure up, then it turns off as it should. Also, something I noticed was that the power windows don't work either, since this issue has started.I disconnected the engine control computer under the hood, all issues remained the same, which tells me that the computer seems to be what has failed. PLEASE HELP! I don't know what my next move should be, thank you