Looks like I've really screwed this up. To try and make it clear what I have done:
1) No iTunes appeared on PC (Vista)
2) attempted removal (correct order)
3) Wouldn't re-download from Apple - didn't work. 3 attempts.
4) used the iTunes Setup link on my desktop which eventually produced iTunes quick link which wouldn't open becuase it said .itl issue
5) added ".itl" to itunes library name
6) iTunes opened but no music (neither purchased or imported from CD) or pics - did recognise my user account though
7) then crashed saying issue with program and Windows closing. Did this many times. At one point saw issue with Corefoundation.dlln message.
8) removed again - but got order slightly wrong - did Bonjour after Apple Application support
9) restarted computer and went through the checks to ensure everything off C:drive
10) tried to re-install from Apple website, didn't work
11) clicked on iTunes Setup again. Some elements loaded (Bonjour, Apple Software Support, Mobile Device & Application support but no iTunes)
12) really desperate now as I've had this account for years and have spent serious money. I have an iPhone4 and a 120GB Classic with Music stored on it if that helps.
Any fixes would be hugely appreciated. They shouldn't let eejitts like me on computers...