Minecraft freezes for no reason

So One day I decided to play Minecraft windows 10 edition because I found a new server. After I was playing for a while I took a break. Then later on I came back online but this time my entire computer froze and I couldn't do anything. So I pressed different keys but nothing happend. Then I pressed the windows key and the start menu opened up. And I noticed minecraft was acting normal but when I closed the start menu minecraft froze again. I'ts like the performance is better when I open the start menu. If anyone knows how to fix this please help me. Thanks.