What is the difference between a scenario and situation?

Solution 1:

In my experience, "scenario" is used in a written guide as in this example:

"In this scenario, the user is trying to create a new record for a client who is already in the database under a misspelled name. How could this user avoid adding the second record?"

A "situation" is more fact-based on a real series of events leading to the event that needs to be resolved. I generally would not use "situation" in a written guide because (IMO) it is supposed to be representative of a set of facts used to train or guide a group of people, not provide anecdotal examples...

...unless I wanted to intersperse real-life examples and then I would use "situation". For example:

"A recent real-life example of this issue was reported by our help desk when a client couldn't generate an XYZ Report after the upgrade. In that situation, Tech Support should suggest...".

Solution 2:

I believe a scenario is considered one of several possibilities.
As in "what would we do in this scenario or that one?"

A situation is a current set of circumstances.
As in "how will we get out of this messed up situation?"

In battle a general might plan for several scenarios, but if he doesn't plan for the right one, he may find himself in a sticky situation.

You can still say "how would we deal with it if we ended up in this situation?" or "how did we find ourselves playing out this particular scenario?" but we're still sort of using them the same way. We're imagining the future scenario is concrete (a situation), even though it's still only a possibility, and we're imagining the current sitiation as one of many (a scenario) even though it is now concrete.

I hope that last paragraph made sense?

The word situate can also be used for placing things relative to each other. For example you could situate a table next to a chair. I think this isn't really the usage you're interested in, though.