If we don't want to rob from the Digital Camera SE site, fair enough, this question as originally written may have belonged there first.
BUT, OP knew the camera date/time was incorrect and so that wasn't what needed to be diagnosed or resolved. We can probably also assume they knew that they needed to correct the date and time on the camera to avoid this in future images.
AND, it doesn't take many words to say you can't get the average camera to re-stamp existing images with a new date and time.
So, that leaves us with only the PC aspects of the solution left before we get to any editing, and causes me to question the validity of closing the question for being off-topic to begin with.
It was clear enough what OP was asking. The issue is most likely to be discovered once the images are on the PC, and a technical solution for the images already taken and stamped with the incorrect date would occur on the PC, and so I have to disagree with those who state that the original question was off-topic.
Editing the question in this case was the correct course, to minimize the off-topic aspects and focus on the on-topic parts.
One sentence beginning an answer would have made it clear the parts of the question referring to the camera can be assumed to be essentially irrelevant at this point. And then the rest of the answer could follow, easily on-topic at Super User.