Thanks for the response. I have tried installing from the original disk then performing the updates and finally updating the NVIDIA graphics drivers but no joy. Interestingly it looks like there are newer updates available i.e. higher than version H but the updater does not seem to detect any higher than H and when manually getting the .pkg file of higher number H onwards they appear to contain PDF files only. let me know if you find a solution and likewise I will update if I resolve the issue

regards
Paul