Thanks for all of your replies. Pleased to report that the re-installation of XP on the RAID array did the trick and everything is working fine. A few looks around some other sites shows that loading XP on to a RAID array does not always go smoothly. In fact my initial problem with this build was the XP installation looping half way through the set up. Again others have had this problem with no real reason as to why.
RAID was set up using "Si RAID configuration facility" activated on the F4 key. 16K chunk size.
Thanks for all your help
Regards
FBW