You should try completely deleting every World of Minecraft client file, and re-downloading it. Before you re-download it, make sure you have the latest version of java to prevent any malfunctions such as what is happening to you now. 

 

You can acquire the latest version of java by clicking here!

 

The fact that it is not responding could also suggest that your computer is running slow. How much HDD space do you have left? 

When this is the case, it helps to change the programs 'priority' in the task manager.

 

To do this, right click on the task bar and select 'task manager'. Once the task manager is opened, you then want to go to the 'processes' tab.

 

Look for the 'javaw.exe' process which and right click on it, once you have right clicked it, click 'set priority' and change it to something higher than it's current setting. Keep in mind, however, it can cause your system to be slightly un-stable/slow except for the thing you are changing the priority of.

 

If none of the above works, try running the World of Minecraft client on a different computer account.

 

Hope I helped!