No start,no power

Hi, I'm one of the auto experts on RepairPal's Car Genius team! Sorry to hear you're having car issues. The most likely culprits on a 2001 Frontier with the symptoms you are describing, are a completely dead battery, severely corroded or loose battery terminals/cables, or a bad ground connection. On a vehicle of this age, corrosion on battery terminals and ground straps is extremely common and can cause a total loss of power even if the battery itself tests okay. It's worth taking a quick look at your battery terminals, if you see a white or bluish crusty buildup, that could very well be your culprit. Also check that both cables are tight and secure. If the terminals look clean and connections are tight but you're still getting nothing, the battery may simply be completely discharged or failed internally. A jump start attempt would be a reasonable next step. However if jumping it doesn't restore power, there could be a blown main fuse, a failed fusible link, or a deeper wiring issue that really needs hands-on professional diagnosis. Given the age of the vehicle, having a trusted shop do a thorough electrical inspection would be well worth it to get you reliably back on the road! If you need any further advice or would like help finding a trusted RepairPal shop in your area or even getting an appointment booked, please feel free to call us at 877-913-1554