Thank you for your question and I understand your concern. Since both, fan and lights quit working at the same time it likely has loose wiring connection supplying voltage to the vent hood. The first thing to do is remove the wiring cover and check and confirm the voltage supply where it connects to the vent hood. If 110-120 volts is present then check all the other wire connections and harness connections.
NOTE: I do not recommend checking and confirming voltages unless you have experience and feel safe and confident in doing so, otherwise I recommend calling a service technician to diagnose and repair your vent hood.
If you do not feel confident repairing this problem yourself, then you can have it repaired at your home by a Sears technician. Here is a link for the website:
Sears Home Services