MasterJaishil

Can someone tell me what to do because whenever i start up tekkit main, it goes to the Mojang loading page, then it stays there for a while. After that it says Minecraft 1.6.4 (Not responding). After a while it just crashes and closes. Can someone please help me. I'm able to start up Tekkit Classic perfectly, but not this Main. I have a 64bit windows 8.1 computer. I also have updated my java to its latest version (as of May 15, 2015) I also have 4 gb of RAM, if that helps. Can someone please help me. Thanks