The story so far: I have a 2 month old pc built by a friend of a friend and so far it has had 2 hard drives and windows Xp pro loaded on it 3 times. It has been passed to me to try and sort it out. I have loaded XP pro again and after a few hours it starts having problems booting with a message about the config.sys file being missing or corrupt......the same problem as before. I have done some diagnostic checks on it....memory....motherboard etc and can only find a strange problem with the hard drive. Whenever I try to check it out it throw up an error message.....Data boundary error.....which refers to another device wanting to use the same DMA channel. I disabled all the other IDE devices and still got the same message. I changed the HD for an old 4GB one and it ran all the tests without a problem....so I assumed there was a problem with the HD. I dutifully bought a new one today and loaded window XP and it all went OK. I ran my tests but still got the same error about the DMA channel. So now I am completely confused....al the tests I carried out on the motherboard passed OK. Sorry about the long message but the full story seemed necessary.....should any of you guys have any suggestions. Thanks in advance....before I pull whats left of my hair out.