Well there’s good news and not so good news. Oddly enough the best protective system
is totally free .... but rather impractical. The best way to protect your systems
from mains surges/spikes etc., is simply to unplug them from the mains and unplug
any modems/ADSL routers from the telephone sockets. However, it is not that easy
if you are not in your property at the time of a storm brewing !
Anti surge protectors
There are a lot of different ones around at different prices all claming to save
your system from mains/lightning strikes. Some are much more effective than others
but the problem is that you have to test them against the storm you are having and
if they fail then the manufacturers of the protectors do not rush to compensate you
for the blown system.
UPS - Uninterruptible Power Supplies
These systems not only offer surge protection but also some offer isolation and,
in the event of power failure, will keep your system running on powerful batteries
for a short period of time - long enough to ride out any power dips and if power
is lost for longer, can maintain power long enough for the PC to be shut down cleanly.