i've been playing guitar for quite a while and i don't know what a "harmonic" is.

what's a harmonic, how do you do it, and i heard theres different types of it?
not too sure but i've only known theres a 'pinch harmonic' and a 'natural harmonic'

can you help me out?

videos won't do because i have dial up.
a natural harmonic is a tone produced by placing your finger above a fret (mostly 5th, 7th, or 12th) on any string and picking the string and then releasing your fret hand finger after picking. dont hold down the string, just place it on the string. a pinch harmonic is when you hit the string immediately after picking the string by holding the pick so that some flesh is sticking out that will hit the string.
often time artificial harmonics (or squealies) are pretty easy if you have a metal effect pedal and a bridge pickup. hold down the 5th fret on whatever string you choose, i like the high e string.when you pick the string, quickly hit it with your thumb to make it squeal. this lets you reach higher notes on a guitar then you could without these. do this in a digging motion with your hand until you get the sound. its pretty cool. thats most i understand of it yet, seeing as i have no use but for artificial harmonics.

hope this helped
so a pinch harmonic is kinda like a hammer-on?
i don't get it, do you have to pick the string openly then place my finger to the fret i want pinch harmonic?
a harmonic is just a higher or lower version of the note your playing. for example, if your guitar is in standard tuning, the bottom E string is a harmonic of the high E string.

a PINCH harmonic (aka: artificial harmonic, squealy) is basically a harmonic but is created by slightly muting the string your playing but it works best when you have lotsa distortion. pinch harmonics are used for alot of metal, hardcore stuff.

how I do pinch harmonics is i hold the pick really close to the tip of it (thus the name "pinch" harmonic) and let my thumb graze the string im playing. you will get it with practice. watch some videos on youtube. thats what helped me way back then.