Audio works but Video won't show.

Hi!, I hope someone can help me with this problem..

I use windows 8 and the day before I used my "HP Assistant" to update some stuffs. Well, i think this is when the problem started, today when i tried to play some videos that i downloaded, the program i was using (windows media player) show me a message that said something about "Missing Codecs". It made no sense because it worked before, so i tried to look around and i ended up downloading VLC which DID play the videos without any problem.
I thought that was the end of the story for my problem but just a second ago i tried to watch some videos online, in a website i normally use, and once again.. the video won't show, only the audio would play..

I don't understand why this is happening.. I mean, the only thing that i did within this days was using the HP Assistant to update some stuffs of Window but that was it. Funny thing is that Youtube videos DO play without any problem.

I downloaded K-Lite Codecs hoping that will fix the problem but i haven't install it yet, i honestly don't know if its actually because I'm missing codecs (for some reason) or what. Will this fix it? Or does anyone have any idea?

Thanks

Oh i forgot, my graphic card is an AMD Radion HD 7640G

I suspect that the HP Assistant has done something to your graphics driver. I recommend downloading the latest driver directly from the AMD website.

Windows 8 only supports a limited number of video formats by itself. You do need to install additional codecs if you want to be able to play everything with Windows Media Player. VLC uses its own private set of codecs, so you can't compare its behavior to WMP.

The K-Lite Codec Pack provides all the essential codecs. The Basic or Standard version should be sufficient for you.