If a desktop the first thing I would look at is the CPU temperatures. Stock coolers on desktops often are not good enough to stop the CPU from overheating on long exports and can cause crashes.
Computer specification and program version, see this topic for what is required and please quote processor and graphics card make/model in full.
The amount of free space on the hard drive(s) you have
Export preset your are using
Was there any error dialog that popped up when the crash occurred, if so what was the message?
If possible, repeat the export and watch the Movie time counter in the export dialog, if it crashes note the Movie time when it crashed. On the timeline zoom in to show about 30 secs either side of the movie time noted, take a screenshot and post it your reply.
Thanks for the specs and images - the lack of an error code makes more difficult to determine what is going on, however the messages would indicate that the program cannot get any more memory to use - do you have a web browser eg Google Chrome or other programs open while exporting?
. . . . movie about 1 hour long . . . .
From the export dialog image the movie looks to be nearer 2 hrs long however this is well inside the maximum the program can handle so should not be an issue.