I cannot find the silent mode option in on-demand scan.
You won't... It's only possible in the Professional version.
Home version only allows Silent Mode of on-access (and email processing).
Besides, whenever I close the on-demand scan box and restart it again, the view report option is greyed out. And it does not remember the last setting.
Work with the results (last report scanning) is another Professional version feature.
But, if you're infected, why don't you send the files to Chest, one by one, be clean and then don't have to see that infected warning again?
Or, better, consider Pro version