Well I can't add anything more than that. The PrePlus is a Pre with just some extra memory. So all here is as everyone says for both phones. And in most cases, even the Pixi.
You need WebOS Quick Install and Preware.
Do searches for those two things and read, read, read..... and ask lots of 'detailed questions'.
Example: do not say 'my phone is broken please help'. DO say 'my phone is broken and here is what is broken, I did X and I did Y and got result Z.... That helps everyone here to be able to help you fast. Give lots of information in messages when you need help, and you will get the best answers back.
Have a great time!
PS One more thing, you can NOT break your phone with 'rooting' or as we might call it 'Homebrew'.