Quote: Originally Posted by centaur78
Right click on wmplayer.exe in resmon and select Analyze Wait Chain...
Post a snapshot of what you see there
Strangely enough, I opened resource monitor again to do this, and now it's working! (I just fixed some broken shortcuts in the Public folder where the videos were - I don't know whether that had anything to do with it.)
The question now becomes, why is media player thrashing the hard drive? I've got 16Gb of RAM, but looping a 45MB video causes WMP to constantly read the file from disk (that's the 4Mb/s shown earlier).