Check your battery, again. I had this EXACT problem two days ago.
BRAND new battery, even, and perfect charge.
Key in, turn to "on"..
PATS light stays on all the time.
NO dash lights (except a MICRO flash of the ABS light.. top right)
no start.. no attempt.
multiple times I check and no start, same symptoms.
So.. I am like.. well.. I hope that's not a PATS issue..
I hook up a jumper cable, JUST in case, and it starts right up..
from then on, no problems... and I don't know why.
Ray