Using CAPS to emphasise a word is fine when you use ALL caps in computing it is considered shouting in many forums and news groups. Not only that large blocks of caps are hard to read.
It is good to invite your friends to use avast, but on the on-demand scans you don't have to scan archives, nor do you have to do a Thorough scan (perhaps the first scan you do Thorough+archives to check your system is clean). After that I would suggest a Standard scan without archives.
Archive (zip, rar, etc.) files are by their nature are inert, you need to extract the files and then you have to run them to be a threat. Long before that happens avast's Standard Shield should have scanned them and before an executable is run that is scanned. Thorough is also by its design very thorough and perhaps a little overkill for routine use, were a Standard scan without archives should be adequate.
I have only ever done a through scan with archives once shortly after installation just to ensure a clean start state, but with XP for example avast will do a boot-time scan after installation if you select it, this I believe will be quicker and reasonably effective. Like everything in life things are a compromise.
