If anyone is experiencing similar problems it could be your media, my drive is a Samsung SDG-605 and it was that that caused my week and a bit of hell and sleepless nights.
Although I read that Memorex work in 99% of all Xbox's it didn't in mine so if anyone has this drive then I would recommend trying those maxell DVD-R's you can pick them up for just over £1 (a bargain imo)
I'm now playing backed up games and mpg's etc with no probs at all.
Thanks to all for their help.
Skars
PS. XBTool Rocks my world thnx for that