I have compelted the game but for the life of me can't find the following..

I have found out how to get to the canon's, green mushrooms & small tunnel. BUT I still need help on the following:

1. The 3rd star in W4-3
2. The 3rd star in the ghost house in W7
3. The 2nd star in W7-A
4. The 3rd star in W8 the second castle before you go over the bridge to W8-5
5. The 2nd star in the final castle

Please please help me, it is driving me mad, trying to find the missing stars

1: World 4-3 Coin 3
Near the end of the level, there should be a ? Switch and a set of four pipes. Hit the ? Switch before the eel appears, then enter the green pipe on the far right. Swim down the left side and into the bubble stream to pick up the Star Coin.

2: Ghost House 7 Coin 3
There should be a P Switch near the end of the level. Hit it, and go right. Go up as far as you can. If you do it right, you'll end up above the door leading to the exit, with an alcove with a Star Coin. Pick it up and head back to finish the level.

3: World 7-A Coin 2
Near the beginning of the level, there is a cannon pipe on the right side. When you shoot up, you collect coins and make new coins appear. Shoot up and collect the coins, then shoot up again and Wall Kick up until you can enter the pipe at the top. It will lead to a room with the second Star Coin.

4: World 8 Castle 1 Coin 3
To get this coin, first make sure you have flipped the red/yellow block near the end of the level to use the lower platform right next to it. Doing that will allow you to ride a platform under the Bboss door, from which you jump on three more platforms to acquire the Coin, then proceed back to the Boss door. If you don't have the switch flipped right, you'll have to start over.

5: World 8 Castle 2 Coins 1-3
This level, unfortunately, is quite confusing, and I don't know how well I'll be able to describe where to go and what to do for the individual coins. It's probably best to check some walkthrough where there's a full level description, and you just get the coins along with it. Sorry!

I think you just have to pay around 5 Star Coins to get in. If you're talking about the one at the bottom, you'll need to go into the first Ghost Mansion. At the start, hit the leftmost block to reveal a Red ? Switch and hit it to reveal 5 doors. Go into the bottom-right door. Next, hit the invisible block that the hands at the top of the screen are pointing to to reveal another Red ? Switch. Take the platforms up and go into the door on the left. In the next room, hit the P Switch to make all the coins turn into blocks and go left until you see 3 lone brick blocks. Stand still and you'll see the third block from the right of a long line of blocks shine. Hit that to reveal a Golden Piranha Vine, and quickly make your way up to it. At the top of the vine is a door. After you go through the door, you will complete the secret exit of the level, which will reveal the path to the Green Mushroom House.this is for w7 first green mushroom