Currently Being ModeratedDec 5, 2012 10:53 PM (in response to David in Vancouver)
That suggests that the problem is local to your user account rather than is system wide.
First thing to do is start up in Safe Mode, then go to
> System Preferences... Users & Groups | Login items
Remove everything in that list, then restart the mac normally and see if it boots.
If not, post back and will look at a few other places that might be
Currently Being ModeratedDec 6, 2012 10:10 AM (in response to David in Vancouver)
Have you tried setting up another user account and seeing if it still acts the same? A follow up to softwater's thought.
Here is another thread with some other suggestions:
If you monitor the "More Like This" box, perhaps you'll find a thread that will help.
Currently Being ModeratedDec 6, 2012 1:12 PM (in response to Eric Root)
I did something better; I erased the disk and did a clean install of Mountain Lion. (I had previously bought a new disk becuase I though that it might be a disk failure). But I still get the same problem. In fact I got the problem during the install. But I could finish the install doing safe boot. Again, I can do a safe boot, but not a standard one. And this occurs before the login.
The hardware check from the original disk says that there are no problems with the hardware.
I will now try a clean install of Snow Leopard and see whether that works.
I'm guessing that it is a hardware problem, because Mountain Lion has worked fine for a few months. But I've no hints as to what it may be.