Can't destroy blocks in Minecraft?

I recently received an Alienware Aurora R4 as a gift, so I downloaded one of my favorite PC games, Minecraft. As soon as I booted it up, I created another world in Survival mode. I went to destroy a tree and as soon as the block was destroyed, another block of wood took its place. I could not destroy the block completely and I only received the element once. Is there any way for me to fix it?

2 things, if it's a server try seeing if many people play on it and/or if you need to be opped to play. If it's a single player world try creating another world.

Maybe you are in adventure mode maybe try /gamemode 0

Yes, you should go to youtube they always have people making videos about problems. Trust me.