T42 -- Settings don't stick

[think9]

T42 and WinXPP

1. The sound on the laptop is gone. I check in Control Panel > Sounds and Audio Devices, Volume tab. Volume is set High and Mute is unchecked; Speaker Volume is High. Then I go to the Sounds tab. I tested some of the Program Events' sound; and I couldn't hear anything. The Volume Control buttons on the laptop is set 2 bars short of max. What else should I check?

2. My Desktop Properties, Appearance tab, Advanced. I changed the fonts and sizes of some of the Items. AFter a short while, they went back to Windows' defaults. Before it happens, I hear a weak sound. What is causing this?

3. I also find some setting that I made on the TrackPoint and UltrNav are also gone.

What is going on ? Come to think of it, every once in a while, I hear this weak/weird sound; and I have no idea of what it is about. [This T42 is on; but I was working on another computer.]