My daughter has an Audiovox D1998 model and isn't

Try a CD disc lens cleaner (can be found at Radio Shack, Wal Mart, Best Buy). Is it still under warranty? If not try your local TV repair shop for an estimate. But beware most shops do charge a diagnostic fee to look at the equipment. Note: Since these units can be found on the net for about $100 you may come out better with getting a new one.