While most video streaming web sites have moved to flash based, some stuck with WMP. Then the problem is likely to be more complicated than just installing newer version. If you have the problem like no video & audio, but it says buffering then “ready”, then the way that might help is forcing WMP to use HTTP protocol only and all multicast by following procedures.

1. open WMP
2. Menu: tools > options (if you can find it, click "alt" on the keyboard)
3. Tab: Network

WMP network setting
    uncheck RTSP/*, but  leave HTTP checked under protocol section
    check "allow to receive multicast stream" below.
4. Done!

happy watching whatever you want =)

Note: if you are one of Thaitv.tv followers and have this issue, this definitely helps.