Explorer thumbnail creation happens automatically, and there's not much you can do about how or when. In general, you have to browse into a folder containing LDraw files, or its parent folder, in order to get thumbnails generated. (In the parent folder, it will generate thumbnails for the child folder so that they can be displayed over the folder icon itself for the child folder.)
I tried reproducing the steps you listed, and I couldn't get it to crash. It does sound like your crash isn't related to memory usage, though. If I can reproduce the crash, I can hopefully fix it, so I'll keep trying, but I'm not holding my breath. By the way, I think you mean MB in the places you say KB. LDView uses 31MB on my computer with no model loaded.
When you uninstall LDView, it doesn't delete its settings from the registry. It probably should, but it doesn't. So, when you reinstall it, all the settings you used before are still there. To go back to default settings, hit the reset button on every tab in LDView's preferences, then hit OK.
I tried reproducing the steps you listed, and I couldn't get it to crash. It does sound like your crash isn't related to memory usage, though. If I can reproduce the crash, I can hopefully fix it, so I'll keep trying, but I'm not holding my breath. By the way, I think you mean MB in the places you say KB. LDView uses 31MB on my computer with no model loaded.
When you uninstall LDView, it doesn't delete its settings from the registry. It probably should, but it doesn't. So, when you reinstall it, all the settings you used before are still there. To go back to default settings, hit the reset button on every tab in LDView's preferences, then hit OK.