Hello, I read most of the reply's and real good input from them. I have a couple idea's too. Where the hard drive's are going bad is it the same power source/ plug-in where this happens? Has the computer been moved to a different outlet, or run an electric cord from another outlet for a while and see. (How old is the building?)
Power spikes or surges will zap a hard drive quicker than you could imagine. I think you mentioned that the printer works on other computers. Even a newer building could have a bad wall plug or plugs.
I may turn on a laptop computer in my home for a while sitting in my recliner but I have all my stationary and laptop computers on a UPS (Uninterruptable Power Supply). That will ensure a decent electrical connection and if not it will allow for a graceful shutdown. It won't allow current that would harm your computer. (A consistent current is key to proper functionality. A UPS will make that happen.)
There are a lot of areas to check but if all is happening from or near the same power source, I'd try another power source for a while even if I had to run some 14 gauge electric cords to do it if I couldn't easily move my systems. The minimum would for sure be to use a surge protector but that is not a long term solution if your current is surging or spiking.
Also along the same line of electricity, I talked with an electrical engineer while I was inspecting his home one time in the Maryville area near Louisville. I took this to heart when he stated it at the time and have used it since (It doesn't cost anything and his credentials were displayed on his office walls from various institutions of higher learning.)
He stated to tie a loose knot in your electric line like the below picture. It was to stop certain surges of current. (It doesn't need to be at the connection, just along the line at some point.)(I will use a line used in Rooster Cogburn; "I ain't going to say if it's true or not, but it's comforting.")