How do you say "Hello" in Thai?

Also, how do you say, "How are you doing?" Thanks a bunch!
Update: Thank you everyone for the answers, it will be hard to decide who to give the big 10 points to. I'm emailing an old friend, she hasn't responded to my emails for a long time, but I know she checks her email. We used to be friends when she was over in the US earning her doctorate. Thank you all for... show more Thank you everyone for the answers, it will be hard to decide who to give the big 10 points to.

I'm emailing an old friend, she hasn't responded to my emails for a long time, but I know she checks her email. We used to be friends when she was over in the US earning her doctorate.

Thank you all for taking time to respond, I really appreciate it! :)
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