wifi connection intermittently randomly stops and later reconnects randomly

When I am at work, my wifi connection will randomly disconnect. Nothing I do seems to make it reconnect. The problem is not the router or the internet service. It is my macbook pro. At some random time later, hours or days later, it will just reconnect on its own. What can I do about this problem? Help. This is wrecking my business. I can't work when my computer is down.