how do I override the antitheft system?
on 1998 Subaru Forester

will not start, blinking lights, battery is charged

Asked by for the 1998 Subaru Forester
I'll assume your key has a computer chip in it. If the chip goes bad or is damaged the only thing you can do is get a new key recoded. for the vehicle.
2 more answers
Try with another key...if still the same, possible issue with antitheft system.
Do you have aftermarket alarm installed? if not, check battery terminals to make sure they're tight.