i deleted something and now cant open itunes

I dunno what I did, My computer has been experiencing what I believe are hacker symptums, I may have deleted something required to open itunes, cause that wont open. The files on the desktop used to have text under them, now its squeezed too small to see and stretched. Files dont open and say"Content" instead of having any of the original files in them, and I believe that my computer says that I am a part of a network when I never advised this. The network folder is empty... But mostly I am confused, and irritated. Love the Apple products, happy with it... Just confused.

I ran "Repair Permissions" the only thing that came up was "unable to repair permissions in SIUD file." Please help IFeelDuM DuM DuM.

Thanks, and keep them Apples growing and I will keep picking them. [snicker]