Not sure now if this should be in this shed or some other one as I've found it's it's not a KDE problem - the same problems exist whatever I try to boot into and gnome just goes into a login loop. I managed to get the logs with a trusty livedisc but even plugging the machine directly to my router gives nothing. A message comes up "No network interface". A look at the entropy log shows no errors or warnings. I also have kdm.log, lspci, lsusb, dmesg and .xsession-errors. I shall not post them all unless someone asks for them. The lsusb doesn't agree with what I know to be on the machine.
I hope there's something I can do as, with no connection, it will mean a reinstall and that would be a shame. Sadly, I don't know where to start.
My SL 6 amd64 K updated with no problem. I'm not going to risk my main machine (x86) until I know what the problem is.