Playback of DVR-MS file freez

Hi,
To anybody who can help me - I thank you in advance.
I own a Dell xps 1210 (Windows Media Center) laptop

These are the specs:
Intel Core 2 Duo T7200 (1.8GHz/4MB L2 Cache/667MHz FSB)
2GB (2x1GB) Dual Channel DDR2-667 Memory
60GB 5400rpm SATA HDD
nVidia GeForce Go 7400 TurboCache 256MB (64MB Dedicated/192MB Shared)

I am trying to playback TV shows recorded with Windows Media Center. They
files are in DVR-MS format (40fps, 8000kps).
Well, the file starts playing alright, but after about 5minutes, the video
start to stall, slow down, then FREEZE! The audio keeps going just fine!
Why is it doing it?
I think the laptop has enough "horse-power"...are there any settings that I
could adjust so that it wont do this?
Any suggestions are very welcomed.
Thanks,
medsdoctor.