If you saved your game before catching the legendary Pokemon reset the game that way you can try catching it again.
beat the elite 4
If you did,just go to the pokemon league then beat the elite four and the champion
You go to your farm save it them bring your legendary pokemon to the front of your Pokemon then it will go in your farm
Yes, there is if you bring the three legendary birds Zaptos ,Moltress and Articuno and ,bring it to 4th F the legendary Pokemon appearing is Lugia which can be captured! Source: Tried in white 2 and black 2
Depends on the legendary pokemon. If it's something like a Raikou or Entei, you probably can't. Giratina, you can go back and catch/beat him. Deoxys, I don't think you can. Latias/Latios, egh, maybe not. Sorry if there's another legendary that you mean, but that's all I can say for now.
No there is not but if you have beaten the E4 ( Elite 4) than go to mount silver and go to the very top and fight Pokemon trainer red and if you have not then prepare for the battle of your time cause he is challenging. If my memory serves me, he has a Pikachu, Lapras, snorlax,charizard,blastoid,and a venasour . P.S the pikachu on his team knows volt tackle.At first he had a exutter when I first fought him bring Pokemon stronger then lv.80 ( level 80 ) and if you have lv.90 or lv.100 " BRING THEM OK".
The legendary Pokemon named Regigigas is at the bottom of Snowpoint Temple, which is in the north area. If you bring Registeel, Regirock, and Regice in your Party, it'll revive and attack you.
At the top of Mt. Silver. He is extremely strong, bring your best team
You can't bring Pokemon from the old games 2 the new games.
After beating the Pokemon league, surf just above pacifidlog town. You will find eventually an island with a huge tower. You will need a match bike to reach the top, where there is a legendary Pokemon (dragon flying type waiting) bring your strongest Pokemon as the tower and rayquaza (legendary Pokemon) can be quite challenging.
Recruit Moltres, Articuno and Zaptos. After that talk to Alakazam in Pokemon Square, who tells you to visit them. The legendary birds give you access to silver trench, Lugia is on BF100. bring reviver seeds and huge apples! Egrentii
It shouldn't be, if you have a team of pokemons that are near the legendary's Pokemon, you should be fine. Also use skills that would do lots of damage to the legendary (weakness), but enough to not get it killed. Try to use conditions on it and wait until it has barely any health. Bring a Pokemon that is fast enough for those that run away. Use pokeballs that benefit your catching, possibly time of day has effects on the success rate of catching it. You can also get one from a friend.