"Changing the configuration can affect the performance of your computer." I always stop before affect. Isn’t it rather effect? The mistake is quickly made; the words are quite similar.
This is how it works:
The verb affect means to have an influence on something: to produce an effect or change. Therefore, my first sentence is correct. Also, look at the following examples:
- The virus affected all the computers in the marketing department.
- The disease only affects cattle.1
- Poverty can affect anyone, regardless of age, race, gender or social background.2
Effect is a noun that refers to "the result of an influence."3 Merriam Webster defines it as "a change that results when something is done or happens: an event, condition, or state of affairs that is produced by a cause."4
- The marketing department felt the effect of the virus immediately.
- Maybe it was the effect of the liquor?5
- Any decision you make has a profound effect on everyone.6
It isn't that simple, of course. There is also a verb effect, often used in more formal writing. It means "to achieve something to cause it to happen.”7
- After the virus was deleted from the computers, the director effected new work instructions. (The effect was immediate. No new viruses affected the computers in the marketing department.)
Are you still with me?
Quick’n dirty: You can safely store the verb effect in the most remote corner of your memory. You will almost never need it. In most cases, affect is the verb and effect the noun.