Laggy Video Playback

I'm not sure whether or not this should go into this forum, but the others seem even more irrelevant... Anyways, I have a problem with video playback. This problem persists with ANY videos, regardless of size, quality, etc. Every 3 seconds or so, the video would skip a little bit, as if it were dropping frames. This is VERY obvious and gets annoying very fast. Is there a cure for this problem? My system specs are as follows:

Dell Inspiron 9300
Intel Pentium M 2.0GHz
1.00GB RAM
nVidia GeForce Go 6800

I can run games perfectly smooth, so I don't THINK it's my video card problem... probably something to do with the settings in the video player? I've tried using both Media Player Classic and the newest version of WMP, and they both have the same problem. This problem hasn't happened before in the past, and it only recently started happening... Granted, I didn't used to use my laptop that frequently, so it might have started a while back and I just didn't pick up on it. Now, however, I need to use this laptop as my primary computer, so I would really like to have this problem resolved. Thanks for any help in advance.

 

My brother has this issue recently,and he solved this problem by stop using WMP,and now he use Nero Show Time.Maybe it's codec issue,so DL K-lite full pack,and tell us what happen.

 

I already have K-Lite full pack, so I don't think it's that.

[EDIT] I then tried what your brother did and used a different player. I'm using VLC right now and everything seems to be working perfectly smooth.