"Q: Why can I only play files I rip back on the computer I ripped them to, and not on another computer on the network (for example)?

A: This limitation is because of the DRM applied to the file, which licensed the file solely for your usage on that computer. To turn DRM off for all content you create in the future, go to WMP7's Tools:Options:CD Audio and uncheck "Enable Personal Rights Management" (this is under Tools:Options:Copy Music, "Protect Content" under newer versions of WMP), which will result in DRM-free content for all content ripped from that point forward.
Generally, I'd simply recommend turning DRM off - going to WMP's Tools:Options:Copy Music and unchecking "Protect Music" - and then rerecording the CDs in question with DRM turned off. After all, even if you recovered the files, they'd *still* be DRMd, and there seems to be no reason for that. "
More at http://keznews.com/forum/viewtopic.php?p=51783

So, was that PROTECT MUSIC ever "enabled"? If so...