2001 Toyota Corolla car wont start makes loud noise..

Hello mt 2001 corolla wont start we just got back for a 600 mile drive I parked the car and went to go to work in the morning and wont start up? All I here is a loud noise like the starter grinding on the fly wheel. This is what I checked I took off the starter mad shur it was good and then took off the valve cover and looked at the timeing chain it looks good.
So what do you think I have three questions?

#1. Is it something semple i'm not thinking about?

#2. So do you think it might be the automatic transaxle not engageing?

#3. I need to buy a new engine?

I just dont see a car with only 62301 miles takeing a crap just like that all fluids looks good with out some tipe of warning.

Any help would be nice thanks