For 3rd party uninstaller I used Windows 7/8 (or XP in your case) Manager. It searches and deletes all related files and registry keys. I never had problems with it only once, as I said. I'm not sure in your case what would work best.
In the end I think you could try different solutions (doing some system backups along the way) and see what suites you best.
what he wanted to delete in such one case you say?
I am very sorry that there is no clear list of files which some
process (for example installer creates/or changes)
on my previous machine i got also xp instelled only once
and then used almost 5 years (I did only manual deletions
just not used uninstallers, it works quite good till today
I only try to watch the list of running processes and services,
it does not slowed down (it seem even working somewhat
faster than new installation on other faster machine) but
then i began to have sometimes some message box on logon screen that some service failed (I cannot how to diagnose it what it
is exactly) also I got bad behabior when ram and page file
ends - it is just blue screen there ;/ except that it is working
quite fast and good .. do not know how to diagnose this problems
and repair it manually :c
My new installation on a new machine works perfectly good right
now though i am often a largely disapointed by the new wersions of favourite soft - some older are often far better than the newer one
(opera 19 ? some older (10?11? forgot) was better for me, Itunes 6 was cool and fast)