Okay here's what I do to vectorize layers in Photoshop. I'm assuming your layers are intact.
Shapes that you've drawn, circles, ovals, etc. are already in vector format.
Text however is not. Do make text vector go to
Layer > Type > Convert To Shape.
It does what it says. You wont be able to edit the text however.
And that's pretty much it. Your situation may be abit more complicated.