Control Panel changes don't stick

3 out of 4 times, when I start my new computer with Win XP Pro sp2, one or
more settings that I made in Control Panel revert to their defaults -- or
something between the default and my setting. I changed the toolbar and
desktop to Windows classic, disabled system sounds and screen saver, etc.
Typically, it will start with just the task bar and windows borders changed
to the default look, while the settings show that classic is selected.
Sometimes it turns system sounds back on. But the setting in control panel
shows neither the windows defaut or "none" (the latter being the option I
selected.)

I am having a similar problem with an application not remembering
customization settings.

I have another app that is suddenly crashing the entire system -- not even
going to a blue screen.

For about a day and a half, I have been getting Dhcp errors or log entries
with Event ID 1002 or 1003. (See post in networking.) Now another machine is
experiencing this problem as well.

Any ideas about what could be going wrong? I've spent days trying to
troubleshoot this and I haven't been able to get a useful response from any
tech support departments.