Your hardware is way too slow for this video. The Atom N270 you have is about as slow as a Pentium III. The video is compressed, so the processor has to decompress it real time, and 1860x688 pixels are just too much for your processor, it cannot decompress 24 frames per second. The thing about netbooks with nvidia cards is that they have either CUDA (a technology which lets the processor to delegate computations to the GPU) or a dedicated hardware chip for decoding MPEG compressed videos, which cannot do anything else, but is especially efficient at MPEG. There is no way to add either to your netbook.
If you really insist to watch this video on your netbook, you'll have to reencode it in another scale, and preferably also in another (older, uglier, less computing-intensive) format like DivX. Your netbook has a 1024x600 screen, so recoding the video in 512x300 should still show up as a good quality. But reencoding is very slow. If you are doing it on the netbook, it will take 3-4 days. So if you have another, faster machine, where you can reencode, and a very strong reason to want to watch on the netbook, this could be a solution. But for most cases, it is just not worth the effort.