Bringing up the 'fresh install' bit made me remember this.
Each time I work from a fresh install I have to go back into Options and:
1. Turn MP voices back on for AI units.
2. Re-select 'Broadband'.
3. Re-tune the 'Controls' settings back up to the 150% or so I like.
Make sure you're browsing through the options screens yourselves if you've done a fresh install...
-Av-