Download and install K-lite Mega Codec Pack ....click
hereThe K-Lite Codec Pack is a collection of DirectShow filters, VFW/ACM codecs, and tools.
Examples of supported video formats are: DivX, Xvid, MPEG-4, H.264/AVC,
MPEG-2, VC-1, H.263, FLV1, FLV4, VP3, VP6, Theora, SVQ1, SVQ3 and
MJPEG.