Thanks all for your help chaps, and it looks as if all is now working o.k.
Was looking at the Win7 thread in SH4 and it mentioned running first with the graphic card on default settings, shutting that launch down via Task Manager if unsuccessful, making any necessary changes to the graphic card then lauching again. So far it seems to be working!!
Thanks again and if this solution has been posted here previously, apologies for not having seen it and giving credit where due.

