Car won't start

I have a 99 Pontiac Sunfire GT that won't
start. At first it wasn't getting spark
because of bad coil packs, replaced those.
It's now getting spark and fuel, but the
anti-theft won't turn off. I found an older
post about it and tried the suggested reset
method. I have a scanner and used it to
clear the codes before eac attempt, then I
even tried the disconnect the battery for 10
minutes. The anti-theft light just won't go
out. Any suggestions would be greatly
appreciated.