The preview is just that, a low quality preview, it runs smaller than full
size physically, 320x240 and at 15 frames per second, so missing every other frame for NTSC.
It will also skip more information if it needs to so that it can play it all in real
The lower the computer specs, so small processor, low amount of RAM, small full hard drive will all have a detrimental effect.
Also the higher the complexity of the movie the more evident skipping will be. So if you add background music and special effects to the clip and then have a transition between two clips, the more chances are that Movie Maker will skip frames and audio on your playback preview window.
The other option is that which some other manufacturers use. That is to have the programme render the changes you make first, so it saves a temporary file of the transition, music and effect combined and then plays this back The benefits of this are that you see all the movie, as it should be. The downside is, if your clip is 20 minutes long and you add an effect, you will have to wait a long time to have the computer render it and play it back!
To check if the file you have captured to your computer is all ok.
Save it back to the mini dv tape and play out on your tv.
If all is well, then there isn't a problem
If it skips here, then there are other problems. Most are computer performance related, so check out