when I clicked on video file nothing
has happened.Is that correct?
Answer
No, that would imply that the effect would have come before the cause, i.e. that the video would have been shown before you clicked to show it.
You should keep the same tense for cause and effect, as the effect if expected to come almost immediately.
When I clicked on a video file, nothing happened.
or
When I click on a video file, nothing happens.
Attribution
Source : Link , Question Author : IAdapter , Answer Author : Guffa