Minecraft runs only on background for a long time, and even if it loads it wont let me load into my worlds.

My minecraft launcher runs just fine, i can change skins and everything and when i press launch it loads quickly, however, then it goes into a background process and nothing happens for a long time, but if i let it be long enough, it eventually loads to the game, however, there i am not able to load any of my worlds or create and load new ones, while it hits 100% and then just freezes and requires task manager to close it. It started happening ever since i bought new notebook and nothing which i found on forums so far helped. Please save me. 

Thank you