1. Regarding VMS Platinum: when I go to capture, say a tape that I took at my son's baseball game, am I capturing the whole tape and then using the trimmer, or do I selectively capture just certain segments of the tape and then just throw these up on the timeline for further editing and effects? Is this a personal preference thing, or is there a right/wrong way that this is done?

I'd say personal preference. Hard disk space is insanely cheap these days. I always capture the whole tape -- or at least whatever is related to the project I'm working on -- and pick out what I need. Pro's, or people who have been editing since the "early" days of 30 GB hard drives, might be more likely to capture just the pieces they want. They might preview a tape, write down the timecodes of the sections they are interested in, and capture just those pieces.

2. Also, I had a clip on the timeline that I edited and added some effects to. I then went to "selectively prerender" it. Another window popped up showing that it was working on it, but after it closed I could not find the avi file. LOL!

"Selectively Prerender" is really just a feature to help you preview your project. It is basically creating temporary rendered files, where needed, just to play back during preview. If it has pre-rendered something, you'll see a little red (?) bar at the very top of your timeline window, indicating that it has that section rendered so it can give you a better quality, smoother playback in the preview screen.

I'm sure the files are there on your computer somewhere -- and you could go looking for them -- but if you actually want to keep a short .avi of a piece of your project, you should probably create a selection area of the part you want to render, click File >> Render As... and select "render loop region only" (not sure of the exact wording)

Tim L