It's been far too long since we've done a condescending post on correct usage of the English language (our last one was on further and farther back at the start of December!) and we felt it was time to do another.
Today we're looking at one of the simplest errors. If you know anything about words and their classification is makes this very easy.
Affect is a verb. It means something is doing something. Something affects something else. Since it's a verb it can be conjugated which means, in English, that it can have the -ed suffix in the past tense. There is no such word as effected.
For example: Drinking ten pints of strong continental lager seriously affects your ability to drive.
Effect is a noun. A noun, put simply, is a thing or a concept. If preceded by the or a then it's effect you need.
Example: The effects of drinking alcohol are detrimental to one's ability to drive.