> Everything worked fine in the guest account. I wonder why.
Because the root of your problem lies in your home folder in your regular account it wasn't perpetuated in the new one. (Only system files are common to the two accounts.) Now, maybe somebody can suggest what's wrong. Time for some cache clearing, maybe? (For my own benefit, did you use your guest account or create a new one?)
> I've always used only one account, an admin account under my name. Is that wrong?
Your default account must be an admin account, but some people prefer to keep it in the background and work out of a standard account for security purposes.
I maintain two admin accounts and use one to work out of and keep the other in the background as a test account.
Your call, really.
