VLC: URGENT: No video on AVI playback

I am on a hot project to create some documentation based on AVIs created with SnagIt 8 that include both video and sound. On playback I can only get the sound. I have VLC 0.8.6c running on WinXP Pro SP4.

I've searched this forum as many ways as possible, and found no help. I saw one suggestion to go into the Windows folder options and make sure the advanced settings for avi files had "donble/single quotes" around %1, but I don't know whether that meant either/or, or whether it meant two sets of single quotes... and in any case, I think it meant I'd need to associate VLC to AVI files on that computer. I don't wish to do so. The only other thread I found concerning this same problem went unanswered a year ago... so here I am asking. I've spent way too much time on this already and am under pressure to get this done overnight.

I tried switching video codecs in the Settings preferences with no luck. There were only three options: Fake, Theora, and x264. Maybe I just don't know how to set one of those up properly. I also tried streaming to an output file, but the file was never created so I can't tell whether it worked. (I fruitlessly searched all the temporary, hidden and system files for the file name, and then for any file created that day. So I screwed up something in that attempt, apparently.)

I also read in this forum that codecs are integrated in VLC so it's not possible to just add one.

Is there any possibility for getting these AVI files to play correctly on VLC, or is there another portable player that will do this particular job? This is the first time VLC hasn't come through for me... so I'm hoping there's something I am ignorantly overlooking.

I am begging for any advice you might be able to offer.

EDIT: I should add that I'm not using Windows Media Player for this because it has a huge control bar (for pause, play, etc.) that in full-screen mode sometimes will drop and hide, but usually won't. The recordings are full screen and this control bar is in the way when I need screenshots. It's not possible to change the zoom on the video because that compresses the display so the text in the screenshots becomes unreadable, and we can't have that in documentation.

So I need to be able to play these back at full screen, or as close to it as at all possible. VLC has a true fullscreen mode, so this is why I am praying for a solution.