Excessively dry air (low humidity) can cause static to build up rapidly. More obviously, lightning can affect a computer through the mains.
You can generate and accumulate static electricity yourself if you drag your feet when walking or by brushing against TV screens or monitors. A sudden static discharge through an electronic component can cause irreparable damage, and static electric fields near to some live (switched on) electronic devices can cause them to conduct too much electricity and burn out.
Note: The amount of static electricity required to damage computer components would not even be noticed by a human.