If it's cranking over then check fuel pressure. If it won't crank then try jumping the car. It could be a low battery due to a bad alternator.
Use this link to find a good shop near you.
https://repairpal.com/repair-shops
Alex
RepairPal Certified shops can diagnose and repair your 2004 Nissan Sentra. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.