Check this bit is set like mine on the tools, options, then the performance tab:
This is the image that the setting should be like, becuase it works fine for me with these settings,
If you cant see that, do this:
1. Make sure the first thing is detect connection speed (recommended) - Check that.
2. Make sure that use default buffering is checked.
3. Make sure video acceleration is full.
Hope this works and helps, Add to my rep if it does the scales symbol