Hey Carlos did you ever change the transmission fluid like Bille-E and I had adviced you last week? If you did then and still have the O/D light blinking you may have the "2-3 flair" problem that is common on most ST's. Do a search here, if not the flair then you may have a shot tranny.
By the way if you did the oil & filter change, did you use the right type?
Did you disconnect the battery for about 15 minutes for some reason or did it as a way to attempt and erase any codes that may be set into the computer? If you did or will attempt to do, the ST will feel differant for a while because it has an adaptive learing system that takes a few days/miles for it to adapt and adjust itself to driving patterns..