[ddouglass]

Are you doing anything like searching when you experience the stuttering?
Have you upgraded WMP and DirectX? Hoster is now set to use the latest versions of WMP and DirectX. This happened with 4.21 I think.
As far as the search, how many song files (all types) do you have in your songs database?
Are you opening Search each time you need to search or do you leave it open out of the way? The biggest problem with the search is the more it has to search through the slower it will go.
If you are searching for Audio songs to play, do you turn off the Karaoke and Video buttons. This would shorten the list for search.
The greying out is Search is not responding because it is looking for your request, so waiting for it to come back is probably the best way.
Cleaning up your files and defragging the hard drive may help and so would a registry cleaner. As Skybird said many updates from Microsoft leave a lot of registry errors. To fix these and other hidden problems try a system cleaning/fixing program.