Rod knock noise

Probably caused by running out of oil. You could of had a oil leak, either while you drive or while it sits, that let all of the oil out. Or, whoever did your oil last either didn't put enough oil back in (kinda unlikely) or didn't tighten your oil filter or oil drain plug completely, causing a leak, and leaving you with no oil. Hopefully you've learned from this... If you hear that noise, even slightly starting up, you need to pull over and shut off the car and check the oil level. At this point, you can add oil and drive it until it dies... Junk it... Or rebuild the motor. If I were you, do not rebuild the motor. Instead, get low-mileage used motor with a warranty. Especially if its your daily driver.