Hi, this could be any number of errors.
The error message says that the hard drive is bad. "ACHI Port 0 Device Error" This is the SATA port that connects your disk to your MB. The error could be caused by bad hard drive, bad cable or bad MB.
Suggest first you reset everything by unplugging the PC, letting it sit for a min and then plugging it in again. When it powers up in the BIOS look for the Fkey that says 'reset to defaults' and hit it. Then hit the Fkey that says "save and exit". Make sure you save. With luck it will boot.
If it doesn't boot then you'll need to disassemble the PC. It's an all-in-one, and you will NEED to find a manual to tell you how to open it up. Remove the hard drive. See if the PC will start cleanly (should come up and say 'no boot disk found'). If so plug the old hard disk back in and see if it fails again. IF it fails then replace the hard disk.
Good luck. Post what happens.
edit: any failing part can cause the entire PC to lock up. It's not unusual for the keyboard to fail if the BIOS is hung. Errors on the SATA port can hang the BIOS. A loose PCI card can hang the bios. you name it, bios hangs. That's why support usually tells you to pull all cables, especially USB, network firewire etc from the PC and recreate. I've had external disks hang the bios with both USB and firewire connections on sony and HP pcs. The official guide to 'no boot' is here:
http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems It will be less helpful with an all-in-one because some of the techniques are really hard when you can't pull parts easily.