Vista - Windows Media Player had taken over my CPU

I've been running a relatively stable Vista Ultimate x64 setup since October. Other than the odd update and program install, nothing out of the ordinary. (Sure, there were incompatibilities, crashes, etc., but nothing really unusual.)

A few days ago I noticed the machine had not entered sleep mode overnight. It should have. That prompted me to look further. I had changed nothing. Yet, my quad-core had it's third core being used at 25% or more of capacity...all the time.

After some laborious troubleshooting, I found out that Windows Media Player was the culprit.

I haven't used the program in several days, and had rebooted at least twice, yet the program still rose from its cyber grave to wrest cpu cycles. What gives? Why would WMP exhibit this behavior?

If a program is shutdown, should it still run?

Any thoughts or anyone else with this issue?

Thanks,
Ken