Hmm... At first I thought it was just the MKV codec was bad, but then the AVIs stopped working. Well, if you can't help, that's alright.
It all really started since I tried viewing the Half-Life 2 trailers on Steam's own media player. I'm guessing that it is the culprit, but I'll just try going indepth with it and get to the bottom of it myself.
Thanks for trying, though, Tsubasa.
And sorry for the trouble, b-sama. ^^;
mamochan: I tried them both already. I think it's just Steam Media Player just screwing up everything.
Tsubasa: I've only messed with my computer hardware-wise. Just doing minor things like cleaning it out, re-organizing the wires, etc.
How many more posts are going to appear before I get to post this? ^^; (Supposed to be the last reply)