The OP also mentioned that if he reboots the router the laptop can start working again. So I wonder if he can get an address on that laptop from another location after the router reboots or does he have to take it back to the location where it does work?
Does he have admin access to the router?
Who configured the router?
What brand and model is the router?
Mikrotik routers - even the $50 versions - are capable of being highly configurable but not in the "normal" way. They sort of march to a different drummer and make Cisco look downright uncomplicated.