Rev Limit and No start

My Car was wunning Fine. I stopped for Gas started it back up and it would rev over 2500 rpms.
I checked fuses and everything. After A while I started it back up and there was no rev limit. Well after stopping for gas and starting it back up. It wouldnt rev over 2500 rpms.
I talked to a mechanic friend. He suggested disconnecting the batter and reconnecting. So I did. Now the car wont start at all. Any ideas?