Anyone help me to solve my problem playing Blu-ray or Full HD file in my Desktop?

Hi there, have trouble actually playing blu-ray movie full HD 1080p or any HD ripped movie file with 1080p resolution on my desktop with P4 3.0Ghz processor, 2GB RAM, and Radeon HD 4770 video card (512Mb). Im using BenQ 4X speed BD-ROM. Also Im using Total Media Player software to play blu-ray movie or Windows Media Clic for any 1080i/p file. These files or Blu-ray disc will actually play but it can't catch up the speed that the video eventually will become choppy or slower than the audio. I have no problem playing 720p movie file. Only @ 1080p. Appreciate any help/inputs then. Thanks.