Default settings keep being applied. Help!

I've downloaded version 3.3.5a from this website.
After completion, I launch the client using "Wow.exe" and the first thing I do is go into settings - put my resolution to 1920x1080, deactivate music, try windowed form (it doesn't work, just shows the cursor so it reverts back if I press ESC or if 30 seconds pass), chose my realm, created my character, logged in for a minute, exited.
Next time I went back in, the default settings are restored, the 1024x768 resolution, the sound, everything - and I have to agree to the User Terms all over again.
This keeps happening.
First I thought it was because I left the torrent to seed and it just overwrote the settings or config file, but after I stopped it, it kept happening.
Can anyone help?