With a lot of help from the hardware section, I've finally got my old Pentium I going again.
From nothing at all it now boots almost everytime and is up and running in safe mode.
(I get a blank screen when I come out of setup, though the changes are saved, and I can't reboot: I have to stop, wait till it "cools down" [about an hour seems to do the trick...] and then creep up on it... :)
When I don't opt for safe mode it hangs eveytime when it finds a comm port and tries to install it.
Is there any way I can stop it looking for the comm port like I stopped it looking for the keyboard? I don't really need it - when I took the MB out of the case i found a small socket next to the keyboard socket (hidden when in the case) and I plugged the mouse into it - it works...
All the best