You need to look at Get Video and look at the settings, options or what ever it's called. Sounds to me as though it's playing all movie files at one rate (movies are played in frames per second). The Nokia files are probably slower, and on your brother's PC are being played at that rate, but your PC is set to play all files at a faster rate, which is why they rush through.
Alternatively, play them in another media viewer such as Windows Media Player, by opening WMP, and then selecting the file you want to view.