Wow, thats a pretty in depth description, im very impressed to see just how much some people know about these things. thanks very much for taking the time to explain it!

In the box in device manager mine says "Ultra DMA mode 5" so it would seem that again my system seems to be as you expected. Regarding codecs, i dont have much knowledge, but the fact that music files from my hard disk seem to play whereas ones on removable (cd/dvd) media are affected by the 'gittering' effect suggests to me that the codecs i have should be adequate. i could easily be wrong tho, and if theres some you could recomend me to download i would happily try.

thanks again

Owen