hard question

so i go and hang out at my friends house and i use rhp on his computer sometimes but i mainly use it on my computer. he is starting to play online chess but i dont know if he will be able to since i have accessed my name on his computer. can anyone help me with this question as to if he can play on rhp or not? thanks

As long he's using his own name and not yours, there'll be no problems.

RHP is mainly concerned with people using multiple accounts of their own, to improve their rating, win in tournaments by throwing games or to deceive people in the forums or by other means. It is an integrity issue.
You can have as many users as you like using one Internet connection. As long as you don't help each other in any of the ways above, you won't feel the wrath of section 3(a).