Basically, make sure all your computer equipment is tied together using grounded power cords
Get a power board that has all the earth/grounding pins tied together and with spike protection.
Even if the power board is not tied to 'real ground' all equipment grounds will be tied together.
Preferably get a power board with some telecom line protection as well.
(or telecom spike protection that can plug into your power board)
Plug all your computer equipment into that one power board.
Your equipment will be protected from spikes across the mains.
All equipment will be protected from spikes from mains to the ground wiring on your power board.
If the mains power is really dodgy you might also consider a ground mat under your work area also tied back to ground wiring on your power board.
Also for personal safety you may be better off with wireless keyboard and mouse.
Remember also when connecting/disconnecting any equipment from your system, to disconnect the mains power feed.
Good luck. All sounds pretty hairy to me!