don't panic. They're all giving you good advice but here's a couple more things to think about. How did the pump die? If the reservoir ran low on water it will fry the pump. The nutrient solution it pumps also cools the pump. If there's no liquid you'll cook it. Is your electrical connection from the pump to the reservoir connector to the arm/light stand to the base good? You can test that with an ohm meter with the unit disconnected from the wall outlet.
After six weeks some varieties of m/j can have lots of roots. If roots got into the pump that'll do it too. The filter pad may keep out pebbles and boulders but roots will get through. Believe it or not, i got this trick from an a/g customer service rep, who said, "some people are wrapping their pumps in pantyhose." i looked at the problem and decided to go with one of my wife's short nylon socks, the ones women wear with flat shoes. You can carefully stretch it over the pump and tower assembly and i haven't had a root problem since. But i throw it away after the harvest. If you can't talk your 'significant other' out of one you can buy them for about a buck a pair at wal-mart. Of course you can go to a hydroponics store and purchase a pump sock/bag for $15 to do the same thing.
What little information you gave us makes it sound like an a/g q/c problem if it's a new unit and a new pump. But if it's an older unit just remember: It's recommended that you change them annually. I keep a spare on hand because i had the same thing happen in the middle of a crop and if you've got one handy it's no big deal. Try customer service but don't tell them you're growing m/j or they'll get suddenly deaf. If they ask what you're growing, which they frequently do, tell them you're growing herbs. If you don't like your a/g then give it to me. I love mine.