Just to add a little information, my companion Ed-E does not participate in combat, I've tried the waiting over 7 days to see if he returns to Primm (he doesn't), and I have fast traveled to a number of different locations, enter buildings, including going to the penthouse of the Lucky 38 which should make him wait elsewhere... I think this is a bug with the companions. Still not sure how to fix it.
I Had Ed-E and I needed to be alone to get into a building. I still had the 'enhanced sensors' perk, but Ed-E was not with me. I hadn't noticed for some time.
People were still reacting to him being there. Anyway, I tried the vault elevator trick, penthouse, waiting many many consecutive in game days, checking the office in Primm, fast travelling - nothing.
So the game is broken. I can't get rid of a follower I don't have, and so I'm stuck. My only confirmed glitch free save was 12 hours previously, and I'd done the whole boomer quest chain and much more in that time.
What I /did/ manage to do though, is stick the game disk through the optical media security shredder at work, which was satisfying and is about all it's good for. Given the other problems, scenery issues, lockups and crashes to XMB.
So now, I don't have to worry about Ed-E any more.
If this weren't software, I'd have returned it under SOGA in the UK as being not fit for purpose, considering the number of problems with it. Somehow though, software companies have managed to get themselves some kind of defacto exemption from SOGA.