If you haven't dived in 7 years, and your only diving experince prior to now was your OW cert course, I would highly recommend you do a refresher course. If you did your training locally, check with the shop that did your training. They may let you retake the course for free.
A lot changes in this sport in a decade. I took a decade off after my cert and my first few dives (1987-89). When I came back to the sport in 2001, recommended ascent rates had changed from 60fpm to 30fpm, Navy tables were replaced by more conservative agency dive tables, 15 ft safety stops were recommended (no such animal in 1987), and dive computers had come in to prominence. Since I have been diving actively (over 100 dives) I have also learned how much of this sport you truely learn by repetition.
If my understanding of your experience is correct, I would not advise simply doing some 40-50 ft shore dives and shallow boat dives. Supervision and repetition of training will definately be an asset to you.