What's with my nikon D3100?

There's something i don't get every time i record 1080P vids with my very own nikon d3100, the videos are very good until i import them to my laptop the video it self start to lag and run really slow at half the original speed. Can somebody tell me why does this take place, i need my cam tomorrow bec. I have a very important project and i need this to be fixed today. And yes it's HP pavilion dv6, running windows vista 32 Thanks. I try running them on both VLC player and Quick time with the same problem prominent

You have to tell your video viewer that you shot your Full HD video at a certain fps.

The amount of data at Ful HD (1080p) being viewed at 24 fps is huge. Sometimes this requires you have at least a two core CPU running Vista 64-bit or Windows 7 (64- bit) with 6 gb RAM

It seems that you cameras technology exceeds the abilities of your older computer

NOTE: This is something that new photographers (videographers in your case) do not know. The newest technology must include not only the camera, but the computer as well.

It could also be, as was the case with me, you're graphics card is too slow or perhaps your processor… Or both. When neither can keep up with the huge data flow that's what happens.

The problem may either be either hardware or software related on the part of your computer. The camera has nothing to do about it. You may have to install a more recent version of the video file's codec into your computer. Let's say your video's filename ends with a ".avi". Look for an AVI codec in the internet, download, install then test the video file. If it runs smoothly good. If not, look for another version of the codec. Doing this will make all media sensitive programs in your computer aware of the video file and will be able to handle it appropriately.

Since even VLC which carries its own codecs does not work well with your video, I'm more convinced that your computer lacks the memory, processor power, or graphics card specs to run the video file properly. You may need to upgrade your computer if the codec solution fails to work.

Try using a Mac with the appropriate software. They are designed with precisely this in mind. A glib answer, but true all the same.