When you go into the temple on Namek, go through the first white portal and then go strait down, then go right until you see the wall. Go up a little and you will see a hand statue with a finger pointing to a part of the wall. Walk toward that part of the wall and you will go under it. Keep going until you find an opening with the green artifact.
Hey DBZ fans the cheat I'm about to give you is invincibility. When you first turn on the game when shenron the dragon comes up press up, down, left, right, B, A.
You can also put in this cheat later on in the game when shenron comes up in a move screen!
Another invincibility cheat is, when you get to the part in the game when your enemies can shoot energy blasts let them aim at you and when they charge up press the fly button and when they shoot the energy blast it will hit you but not hurt you. Unfortunatly the cheat will cancel out when you leave that screen.
When you fight Raditz in the begining, use your Solar Flare to freeze him, then go and punch him. Make sure he doesn't unfreeze while you are by him or he will take a good chunk of your health. Be sure to have at least two Sengu Beans and a couple of herbs. If he is too close you can fly away, he can't hit you in the air.
Before you fight Raditz through the old mans dinosaur skull thing, save the game then go through fight him. If he's too hard then restart your game. Do you remember that brown dinosaur that was just before the town? Go back to it, but stand in the shadow of the trees! Slowly walk twards the dinosaur and I mean SLOWLY. When he starts walking, stop and let him stand on top of you. Right now you're probably thinking I'm crazy right? Well then look, it's not hurting you! Just punch it to death and get 500 exp. DO NOT MOVE WHILE IT'S ALIVE!!! Repeat untill you think you're at a good level (that could take a while) I usually do that untill I'm about level 15. I makes Raditz really easy! And it's not as hard later in the game. And you have to remember that there's not much that you can level up on between Raditz and Vegeta & Nappa.