How to connect your laptop to your computer?

I have a Nikon Coolpix P530. I want to record via my camera but be able to see myself on my laptop live as I record. What software do I need/ how do it I do it? Thanks in advance

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This picture already exists in this location. Would you like to save a copy anyway?

I have a Nikon Coolpix S4000. I'm trying to save a video to my computer but I'm getting the above message, even though the video has not been saved on my computer. It's an avi.file but somehow my computer is not recognising it.
Added (1). There has never been a copy saved… My computer isn't recognising it.

I've tried saving with a different name but that doesn't work either.
Added (2). I found someone with the same problem as me…

"I'm so frustrated.It's hit or miss transferring videos from my Canon powershot to my computer. I successfully transferred several videos but then there are others that do it really fast like the computer isn't really downloading a video, and at the end after it downloads to 100% the following message pops up:

"This picture already exists in this location. Would you like to save a copy anyway?"
With the option to choose from:
"yes, yes to all, no, no to all"

I don't have it already in the location - I am downloading it for the first time (it says picture instead of video because I download all my videos into my "picture" file, unless it is considering the video as an actual picture and not a video?

If I click on "yes", it'll give the icon of the video on my picture file but unlike the successful transfers, it won't show an image of the video but instead the icon is the windows logo and when I try to play it it says my computer doesn'
Added (3). Hi Elvis, downloading Quicktime will not help since my computer is not saving the file.

Read more: This picture already exists in this location. Would you like to save a copy anyway?