After research, i have the answer... it was zone alarm !!!
the only solution to my problem was to uninstall zone alarm (just shutting it down didnt do it, possibly some of the program stil in memory...)
rebooted & then tried to install DoW & Fable... both installed 1st time with no errors !!!
reinstalled zone alarm & my PC was still running happy, problem resolved...
onyl question, can i reconfigure zone alarm to allow these games to install whilst it itself is installed & running, that i shall have 2 get around to investigating but i think i will pester zonelabs ppl 1st