In case it's helpful, I thought I'd post a mention that when I tried installing the 7.04 patch, it hiccuped over a .dll that it said was running and couldn't replace.  I tried a switch everything I could think of off and re-run and ended up with a sick system.  The odds are that the problem is my system ... new and tetchy ... but I have contacted Digital Workshop, who great as always , have said they will investigate and get back to me.  If they come up with anything that might be useful to the rest of you, I'll post it here.

LRH