In "A Rose for Emily" by William Faulkner, the problem began shortly after what sad event happened for Miss Emily?
In "A Rose for Emily," by William Faulkner, Miss Emily experiences several "sad events" and several "problems," so I am not certain to which one you are referring. All of them begin with her father's death but were caused by his life.
He raised Miss Emily to be an Old Southern lady who never dealt with unpleasantness and was always above the common folk. Because those were his views, none of the suitors who came to visit Miss Emily were ever acceptable. When he died, her father left her with a house but with no one to share it with; that is the beginning of her problems.
We did not say she was crazy then. We believed she had to do that. We remembered all the young men her father had driven away, and we knew that with nothing left, she would have to cling to that which had robbed her, as people will.
But it will not be long before the town loses its sympathy for Miss Emily.
When she refuses to let anyone take her father's dead body out of the house for three days, her problems continue. And when she refuses to pay her taxes because she had been told by Colonel Sartoris (another Old Southerner) that they were paid, she causes trouble for herself in the town.
When she begins an affair with Homer Barron, Miss Emily is seen as acting scandalously, anything but a genteel woman of the South. When the town sends in the Baptist minister, presumably to give her a lecture on morality, "he would never divulge what happened during that interview, but he refused to go back again."
When Homer Barron wants to leave her, Miss Emily takes matters into her own hands to ensure that he will never leave her again--ever. This creates a problem for the town (though they do not know the cause) because soon a stench emanates from Miss Emily's house and no one quite knows what to do about it. They are forced, by feeling rather than law, to sneak over and sprinkle line around the foundation of her house at midnight.
Pick any sad event in Miss Emily's life, and there are plenty of ensuing problems from which to choose.