Red X and circle!

So, I dropped my ipod in water and now I have a red x and circle symbol with the words apple.com/support/ipod. I have searched this website, and I know that it is a problem with the hard drive and I need to either a.) restore my ipod, and or b) replace the hard drive, but I don't know what to do! My computer will not recognize the ipod. I understand that you can replace the hard drive, and I can't really send it in since it is water damage. Can I do it myself? How do you replace a hard drive?