There are far better players out there, such as VLC Player and Media Player Classic.
Quite some time ago, I upgraded to WMP10 from 9. It seemed to work fine. Then one day, a pop-up appeared advising me that a WMP update was available. Like a fool, I checked that I wanted it. Apparently, this tried to install WMP11. The application stopped working. I could hear the audio on video clips, but no picture. When trying to start WMP, it went directly to minimized on the task bar and never started. Clicking on the task bar icon caused it to speed off diagonally to the top right of the screen or diagonally back down to the task bar from the top right. I was able to revert to WMP10 and all was well again. Now I have the same problem, although I didn't knowingly try to install any WMP updates. I tried to revert to WMP10, including patches, but it doesn't seem to work. Windows XP, SP2, with all known updates.