As VS Like

Like = preposition (a word that ‘positions’ or situates words in relation to one another)

As = Conjunction (conjunction is simply a connecting word)

Use like, when it refers to noun or adjectives only.

Use as when it involves verbs, adverbs, clauses etc (actually anything other than nouns & adjectives)

Eg:

He is like Hulk.

He fumes in anger as if  he were HULK.

It acted just like my computer.

It acted just as I would expect my computer to behave.

like can not be used to give examples. Rather such as is the correct word.

One last point:

Other than the above use, as is used sometimes serving as a preposition with the meaning of “in the capacity of”.

eg: Modern critics are amused by early scholars’ categorizing Tacitus’s Germania as an ethnographic treatise.