Don't bother finding people by user name iff the guy's set a custom user url, then it's easy. get the steamcommuity.com URL and type it in via steampowered.com and add them if not, tell him to fuck off and set a custom url. if he won't get their user id and find them properly: http://steamidfinder.com/

elezzzark's url is: http://steamcommunity.com/id/greasy_bomber

so his alias is weather report (yhou'll never find him from that_) and his account is still the same damned thing: greasy bomber