Thank you all for your feedback. I spent this weekend tuckling thumbnail/preview issues and made no major progress.
kranu, a good suggestion. One problem, however, is that the "Installation Successful" would appear in some fixed languages. At the moment, the 2 seconds progress window (BTW you should have a ver fast PC; it stays approx. 5-6 seconds on mine) shows messages in whatever language that your Windows is in, because those messages are actually from Windows itself. Any customized message needs to be supplied by me.
I can write English and Japanese message, and it will be a good start?