playbac k and midi input not working

I may have changed something in the edit/preferences/ I/O screen.

The playback button and enable midi input buttons on the toolbar are dead.

I have uninstalled both musescore and my midi drivers multiple times
the I/O screen will not reload to the default settings or reset to default.

OS: windows xp pro (version 2002 SP3)
midi input: Yamaha DGX-203 digital grand

Is it possible something is not getting removed when uninstalling?
that is retaining the preferences
Thanks for the help