I'm having a problem with my Zelda rom: I can't seem to get into the water temple. I've beat the Ice Cavern and I've learned the song and I've got the boots and I've unfrozen the King, so what's left for me to do?
To my best recolection, I believe you have to have your iron boots (or whatever they're called), put them on and go right down to the bottom - now the only item in your inventory that will work underwater is the hookshot so I think you have to hit something with that, can't really remember.
Check www.Gamefaqs.com This is in the wrong forum as well, this would be more appropriate in the gaming section.
And btw, I don't think is a problem with the Zelda ROM, is just that you don't know how to continue the game, however if you suspect that your ROM is damaged you have to check it using GoodN64
Use the Ocarina song to warp to Lake Hylia. Put on the Zora Tunic, and the Iron Boots. Turn so you're facing the warp to Zora's Domain, and walk into the water. When you land, turn round, and then use the hookshot to hit the diamond above the door. The Water Temple entrance is just below it.