KenK expressed precisely :
When I hear thunder, or I'm temporarily away from my XP Home computer and
thunder is predicted, I turn the system and UPS off and unplug the modem
telephone line. Overkill? Before I did this I lost the built-in modem to a
nearby lightning strike (I assume).

However most businesses and many other systems are left on durng storms
evidently with no problems.

What do you do?

TIA

I unplug My power to My radio equipment, and unplug the coax.