Change of Message Set Up Msgs. were del...

I will try to explain what I think is wrong with my computer. Sometime ago, I was messing around, and changed the Message system which I had before; the one now does not have a back arrow at the top left hand side; also it doesn't have Forward or Compose. It's pink (which means I made it that way) I want it the way it was before....
Yesterday I tried to erase some of the older e-mails, as it was almost 3,000 on it, and I hit Control Delete,thinking it would just delete a page, and it deleated everything...............
Also, this new kind of Yahoo e-mail is devided in half, I want the kind I had before.
All of this is good and kind, but I know it will cost alot, so I won't be able to afford it; I'm on unemployment.
So if any generous soul would try to tell me what to do, I will.
Thanks and God Bless!
Mary Helen