Error: Could not find or load main class net.minecraft.client.main.Main
Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release

What does any of this mean I am so confused
I have been playing minecraft for a long time, I just got a new computer and now I cant even play help soon

For the versions thing I just picked at random since it affects everything