Thanks Scott for the rreply.
No luck I'm afraid with the above suggestions, which does indeed, sugest, that it's something going amiss with my PC, as I have changed nothing on the keyboard part since upgrading my PC. No conflicts listed in Device manager or anything, so can't think what it is really. I'm wondering if its my 64 Bit Processor/Windows XP PRO (instead of "XP/Intel Pentium 4 Home") that I had, that's causing the probs. One thing for sure, I won't be able to use this midi device anymore if it stays like this.
Thanks scott - all the best