It sounds like the cards are not functioning properly, like I said before. If you tried plugging them into multiple systems that are able to run identical cards in the same slots, but these cards are unable to do anything then that would indicate that the cards are in need of repair. You can try running them on a new OS, but since you are in windows 10 are you able to see the GPUs under device manager? Since they are receiving power, and the fans are turning it is possible that the drivers are just not installed properly, but device manager should help us get a clearer picture of your situation.

Even turning off the PSU is not enough to prevent shocking the cards, even shocks that you are unable to physically feel, because of your threshold for "pain", are well above the amount necessary to kill computer components. Anti-Static bands, discharging your static electricity and making sure you have clean hands when you get inside your computer are a must. Were these cards working properly just a few days ago or have they always been giving you a tough time? What happened between when they were working and when they no longer were functioning as intended?