Greelade, If your player is showing 8GB it has a memory chip hacked to read larger than it's trye size. these players only support a maximum 2GB memory. You will find lots of posts regarding hacked players in the forums.
Your video problems are more than likely being caused by this as the video is becoming corrupted when you load it to your player.
You can check your player like this:
http://www.mympxplayer.org/feedback-...rs-vt2828.html
And remove the hack to take the memory back to it's true size like this:
http://www.mympxplayer.org/how-to-re...ck-vt2400.html