Nissan Repair: 2001 Sentra SE Wont Start, ground wires, battery terminal

Question
Hi there - Long story, try to keep short!  200k miles, great car.  Problems starting - was getting no spark or gas, but turns over.  Disco battery, charged it 24 hours.  Started up.    Runs about a week, then won't start but still turns over.  Check ground wires, replace battery terminals, new battery.  Still turns over, won't start.  Garage tested battery and alternator both are good.  Said the starter is going bad.  It turns over but sounds odd, different than when it actually starts.  Any ideas?  I'm ready to just buy and put in a new starter, but it's expensive.  thanks!

Answer
Steve,

If the engine turns over but will not start could be a defective key.  Check by using your other key to start.  The BCM could have lost the code for the key you normally use.  If the starter sounds strange be sure the fuse links at the positive battery terminal are good.