You certain? I ran NWN on ME for a while and didn't really have that trouble...but then my uncle and aunt always have tons of photo editing and film editing stuff, so maybe that had something to do with it as well.
Addendum: Oops, didn't realize that you d/l'ed a program to read them...I suppose that goes hand in hand with the same thing with photo editing programs as well.
As an aside...I've never tried it...does XP read TGA files?