[-Prodigy-]

There are couple of ways to do this, you can try the following:

pawn Код:

//On top of your script
new bool: gRegistered[MAX_PLAYERS] = {false, ...};

// When they connect
gRegistered[playerid] = false;

// When they register
gRegistered[playerid] = true;

// When they disconnect
gRegistered[playerid] = false;

// OnSpawn
if(gRegistered[playerid])
{
    ShowPlayerDialog(playerid, 1337, DIALOG_STYLE_MSGBOX, "Rules", "Rules", "OK", "Close");
}