Hello Anthonyand welcome to the Vista Forums
The easiest method to correct this, As the problem is very recent, is by use of vista's System restore
Have a look at the tutorial here ...
System Restore - How to - Vista Forums
When performing the restore select the point closest to the install of itunes but before this time, you may actually find a restore point that states install itunes or similar.
Note that as this resets the system to a point before the itunes install it will remove that install.
there have been a few problems with some recent itunes releases not being fully vista compatible so if you need to re-install you may want to check that you, or your son, have the latest release before trying again.