HG 2022 p30 gives:
"Hardened Systems: If a system is listed as being hardened (as with /fib computers, for example), the crew may choose to allocate any Power to
it before any deductions for Ion weapons are applied. This ensures a hardened system will always have enough Power to function, provided that the Power was available before the Ion attack."
Can you harden a power plant? You do not allocate any power to the power plant, therefore how can you harden the power plant? The rule says that you can allocate any power to the system before the deductions from Ion weapons happen. Do Ion Weapons just not effect power plants? Also, if you were hit with Ion Weapons on the previous turn and lose more than your total power points generated in a round and you fire after the enemy ship, those power points to do replenish until after the enemy ship's next turn. So where does the ship get the power points to allocate after this turn's Ion Weapon attack? It didn't have any left over from last turn and it doesn't get new power points until after their turn is complete.
Look at that last line after the comma. "Provided that the Power was available before the Ion attack." If their power doesn't return until after their actions, they can't allocate anything. Power can fail to return in two ways due to Ion Weapons. One, Effect 6+ lasts D3 rounds. This would mean no Power available to allocate to your hardened systems. Two, Attack the enemy after their action and reduce their Power to 0. They will use their power on the first turn as you haven't attacked them yet, but on the second turn, because their Power will not return until after the enemy ship's actions, they have no power to allocate.
So my reading is that ION weapons cannot shut down the ships computer if VIRUS has hardened it as the power is ring fenced. Any hardened systems would also continue to function normally. You would need to destroy the power generating capability rather than just continually drain it each turn.
Keep draining it each turn until you can disconnect the power source. A Vacc Suit doesn't require electronics, nor do hand tools and therefore cannot be infected (as far as I am aware). A ship with no power that can't maneuver is pretty easy to just keep shooting.
There is also the emergency power system option that allows 5 rounds of function after the power system is knocked out. That would logically be on separate circuits and could itself be hardened allowing Virus 5 rounds after you destroy the power generators. High Efficiency batteries could also be hardened and provide an additional independent power supply. If there was a single robot or probe aboard it would be certainly be infected and Ion weapons fired at the ship would not affect it. Infected robots, hand computers, augmented humans or even portable lighting can carry the eggs and are a transmission vector. If the ship were threatened it might launch all drones and robots in life pods to try to preserve its existence. Tracking and destroying them all might not be practical so VIRUS would live on.
This was a good idea until I went and read the rules for the Emergency Power System.
EMERGENCY POWER SYSTEM An emergency power system allows a ship to keep functioning even when its main power plant has been taken completely offline and is a cheaper alternative than a second backup power plant. If the main power plant sustains a critical hit of Severity 3 or greater, the emergency power system automatically activates and allows the ship to function normally for five rounds with 90% of its normal Power. If the power plant sustains a critical hit of Severity 6, the emergency power is taken offline as well.
A vault could protect hardened components until even after the complete destruction of the ship. If the hardened computer and some hardened back-up batteries were placed in a vault they would also survive and be able to operate beyond the total destruction of the ship.
Components in a Vault would be the same as components not in a vault. Vaults are no protection versus Ion Weapons, so the hardened systems would still have the same problems as those above.
How are you boarding. If it is by assault ship then you are bringing power and computers to VIRUS. If you are space walking then you are bringing Vacc Suits that also require power and likely some electronics. VIRUS would probably lie low. You would "vanquish" it and then it would infest your ship when you returned to it in jubilant celebration. maybe not that same day, but one day you would get the glitchy screen and realise you had just added another vampire to the fleet.
Canaries are a thing to make sure that you do not bring back the Virus, but basically, just permanently fry the electronics (this is how they dealt with the Virus in Virus on Virus fights) then throw them in a deconstructor and call it done. The corpse is chewed up after the Virus is killed and you have new raw materials to use in your Fabricator.
When faced with an infected ship or facility, nuke it from orbit... it's the only way to be sure
This is one way to do it, but nuke-proof bunkers are a thing. You have a good point though, Radiation Weapons also work on Robots and electronics in ways different from how they work on biological lifeforms.
