You'll never get Photoshop 7 to work with Leopard. It's just too old.
If you flip your PowerBook over, and remove the main battery, you can open the little door where the Airport card is installed. You don't even need to remove any screws to try this. You'll see the small antenna wire that plugs into that airport card, so you gently disconnect that antenna, then grab the clear tab, and slide the card out of its slot. Push firmly back into that slot. If you get confused which side is up - the bar code should face out when you slide the card in place. You'll probably hear a faint 'click' when the card is fully seated. Reattach the antenna wire. Close the little hatch, then reinsert the main battery.
Restart your PowerBook while holding the Option-Command (Apple)-P and R keys. You should hear the startup chime sound. Keep holding those same 4 keys until you hear the chime 2 more times, then release the keys to let your PowerBook boot normally.
Try your Airport card.