Gateway 6400 Mpeg Playback.

[DARUSSIAN]

Ok, I got that Gateway 6400 server, and realized it was not the machine I was looking for. In fact it runs as fast as my old P2-300 . But anyway, every time i attempt to play an mpeg file in media player, it starts up in a big window and plays a black screen. However if i click on the file, wait for it to show up in the little window and then play it, it runs, but if i maximize the window afterwards, it becomes extremely choppy and slow. This only happens with mpeg and vcd files, divx files run fine. I am runnin win 2000 and never had this problem with my other pc. Any help would be appreciated. Also, what audio card would you guys recommend for this machine. Thanks