Minecraft keeps crashing and doesnt fully load

I tried to download mods, but after getting it and trying to get on minecraft to play, It loaded little then right before it went to the home screen where it show single player, multiplayer and the others. It as loading very slow then it said it wasn't responding. I tried deleting the mods, restarting my computer, and using the old launcher and it worked with the old one. The new launcher it doesn't work for me. It just loads a little then stops and says that minecraft has crashed.