There is a fix to re-set WMP 12 to default. Means you lose all your lists you've created but you can start again. If you wish to re-set to default then type msdt.exe -id WindowsMediaPlayerConfigurationDiagnostic in the start search bar. Selact the msdt.exe in the list and a window opens to reset WMP. Select the 'next' tab select 'apply this fix' then click on 'close the troubleshooter' ignoring if it shows further problems.
How to watch Wimbledon 2015 live online: follow the tennis from your laptop or PC