for example: a player play in this site an his rating is 1100 but stop of use that account, after two years he use that old account in a tournament and win it, ¿that is cheat?
I don't think it's considered cheating, his rating would reflect his skill in a few games anyway if he is better than let's say 1100. It is kind of a drag if you lose a lot of your rating while playing him in a tournament though
The rating should correct itself somewhat quickly. Only the first arena tournament pairing takes rating into account, the rest of the pairings depend on the position in the tournament.