a Duron 600 MHz is not likely to be able to decode h264 video streams without serious stuttering.
If you want, you can try these two options, but chances for success are low:
1) download CoreAVC from the file attachement. Unzip the file and copy CoreAVC.ax somewhere on your computer. Use the Insurgent -> press the Register button -> brose to where you put CoreAVC.ax. Now go to start -> all programs -> cccp -> ffdshow video decoder configuration -> Codecs -> set h264 to disabled -> Apply -> Ok. Try to play the file in MPC. If playback still stutters, you can try method no 2.
2) get mplayer from here
. Unzip it somewhere. Go to the folder where you have unzipped it, look for mplayer.exe. Drop your file over mplayer.exe. Playback should start. This player is controlled through keyboard shortcuts. In the folder where you have unzipped mplayer you can find the manual to mplayer where those shortcuts are presented.
If both methods failed, then you won't be able to play h264 video on your computer. See maybe there's a xvid version of the same file done by the same group or another group. Xvid encoded video should play, as long as they are of "normal" resolutions like 640x480.
The best solution would be to upgrade your computer. A Intel Pentium 4 processor with 2.4 GHZ CPU will playback such files very well and should be at an affordable price. Don't look at cheap AthlonXPs, Celerons or Durons. They're money wasted. Of course, if money are not an isue you can go way way up the ladder of CPUs. Just dont go below or you'll soon regret the investment made.(Removed attached CoreAVC. --Lord)