你怎么样？and 你好吗？could be used as general greeting. The difference is: when people say 你好吗？mostly they just want to say "hello", and you can just reply with "挺好","还好","好",etc. While, when people say"你怎么样？" it means they knew you before(proberbly your are friends), they are caring about how everything is going or did anything changed for you( your job, your health,etc), then you are expected to reply with some specific answers, like "I made a new girlfriend","I was promoted","I moved to the west from the south of the city."etc

“你好吗” just only means "how are you" “你怎么样”means "Are you ok?" or "what about you?"

in daily life you say how are you to someone ， this how are you has the same meaning as 你好吗？ 你怎么样 ？ is the literal meaning of how are you 。 if somebody seems to be in trouble， you can say 你怎么样？ or when you visit the sick， 你怎么样了？is the first sentence you can say 。

“你好吗” 一般表示打招呼 “你怎么样” 一般表示关心问候对方

the chinese is a character ,it expresses the meaning of picture. “怎样”and “好” .they present difference meanings of picture . but english is not ,it presents pronounce of words. these are differences between them.