What You Need To Know
Document, Document, Document.
Always record any configuration changes (especially passwords) that are made to your systems. It is extremely important to record passwords for networking equipment like routers and firewalls. Many times, if these passwords are forgotten or lost, the only option is to reset the device to factory defaults. Depending on the complexity of your network, reconfiguring those devices could get expensive. The more documentation you have available, the easier it is for technicians to familiarize themselves with your computer/network environment, and provide more efficient service. Always keep your documentation in a secure and private location.
Never Trust ANYONE who Contacts YOU Over the Phone.
If someone calls you stating that your computer is infected or that your systems are malfunctioning and that they want you to allow them to remote in and fix the issue… DO NOT let them have access to your computers! This is one of the most prevalent scams out there today.