ITunes does not start run on Windows Vista at all

Question

I've been using iTunes on Windows Vista for about six months. A couple of weeks ago it stopped running: I run the program, see the animation-formerly-known-as-hourglass for a couple of seconds and then - nothing. I can see iTunes in the process list, but nothing happens nor can I shut it down (it does nothing when I try to shut it down).
I've tried uninstalling and reinstalling, but that does not help. The program did run on another user account, so this is probably related to my profile. I tried moving the two iTunes profile folders I saw listed somewhere (can't find them now), but that did not help.
Yesterday, I got a pop-up saying there's a version 7.5 available. I installed that, and much to my surprise it ran normally - once. After that one time it again refused to do anything more than what I wrote at the start.
So what gives? Should I throw my iPods into the nearest lake?
Any hints on how to solve this frustrating issue will be greatly appreciated.

Answer 1

I've tried everything I can now. I've uninstalled everything that has anything to do with iTunes, then reinstalled (as per the relevant article). I've even tried installing an older version, but no. Whenever I try to run iTunes, it shows up in the processes - and can't be terminated except by shutting the computer down - but does not open.
It still seems my only option is to throw my two iPods into the lake. This is infuriating.