good vs. well

For the most part, good should be used to describe a condition or passive state, as in "So, that new Angelina Jolie film is good, eh?", as opposed to well, which should be used in instances such as "My computer is running well", as an activity or state of being being described. In these instances, "good" was an adjective describing the noun, and "well" was an adverb, describing the verb. Thus, the reason why it isn't "My computer is running good", as "is running" is the first two terms in the verb phrase. The adverb completes it.

Unlike When to use "who", and when to use "whom", this simple grammatical mistake may make one appear illiterate or unschooled, etc.

The word good is an adjective, and the word well is an adverb. The opposite of good is bad, and the opposite of well is badly. The link between the two words (and the difference between the two words) is thus more obvious in the negative form, and it seems to me that people don't confuse the negative words as much as the positive ones. (To make matters more confusing again, there's a word 'goodly', which according to Webster 1913 can be used as an adverb or an adjective. However, the use of the word as an adverb is marked as obsolete even then, and its use as an adjective is probably obsolete these days.)

It is possible to do something good badly - for example, rescue a person from a burning building but bang their head on the doorframe as you carry them out. The act of saving someone is a good thing, but the manner in which it is performed is bad.

Likewise, it is possible to do something bad well - for example, a robbery without any clues. To rob is bad, but the way in which this robbery is committed is good (or, at least, efficient).

Keeping these examples in mind can help keep the meanings of all the words clear.