Check your command key. It is possible that something is pushing down on the button in between the key. If not then check your Bluetooth settings and replace the batteries of the keyboard to see if that may be a problem. If possible try using another keyboard and see if it gives you a problem with the space-bar, if so then it could be a software setting, maybe in accessibility settings. Hope this helps!

I don't know anything about that computer in specific but if all 3 computers of yours stopped working suddenly then it is possible that you may have a power problem where there may have been spikes in voltages coming from your outlets. I suggest that you test your computer's power supply to see if it has a problem or if it happened to fry any of your components. You can also check this guide that I found on your computer that may help you find out if your computer had a power issue. Hope this helps!