Hooking Up My PC

Nothing Physical to the hard rive just changing a couple pictures and icons around.I know changing the theme lowers system performance and thats not what im looking to do. once i get my background fixed i will have a kool image to look at so i wont have to much to complain about.

(1) what i want to change is the Boot screen. If seen things you can download for it but there only applications and i don't know where to put them. or atleast i haven't come across something hat will tell me where to put them or do it for me.
Does anyone know such a program or exactly were they should be placed.

(2) second i would like to tidy up and or change my start menu its a real mess with software and its really annoying. Does anyone know a good program for that?

(3) I also want to change some icons around does anyone know how i do that without altering the theme of my computer?

I run Windows Xp Service pack 2. i have an older computer wile i awate my laptop so changing the them would take a toll on my performance.But then again would these changes do somehting to to my performance aswell or will be clean with these tiny changes.Also iv been Looking at Security , maleware, and anti virus things and wanted to know a couple of things.I want some good ones but not like Zone alarm where even though its good its a performance HOG. or Nortan witch takes 3 days to finsh a scan.