Occasionally I participate in seminars on computers for building and design professionals. These seminars usually divide up into roundtable discussions in which individuals can ask the "dumb" questions they were afraid to ask with hundreds of people listening. Here's a sampling of the most commonly asked questions. If you're still trying to decide which computer to buy and what software will best serve your needs, the answers may help you make up your mind. Q. I have a small construction company with just a few employees. I run it mostly by myself, with some help from my spouse, who keeps the books. I don't know anything about computers, but I know I need to