First, do not panic. Do turn off your internet access, but do not panic. When you turn off your internet access, make sure you segregate your system from your other computers (in all forms, including smart phones) and through all means. Disconnect wires and turn off radiating elements, such as wireless access.

Next, assess and recover. If this means getting professional help, do it. There are a variety of organizations that can assist with recovering both systems and data.

If you need to research sources of help and you would normally use your computer to search the Internet; do not. Go to your local library or an internet cafe. Do not reconnect your system to the internet until you are certain that it is safe to do so.

Consider contacting law enforcement or getting legal advice depending on the extent of the problem. Do not try to go it alone if the problem is extensive or expensive: there are people who really understand the problem that can help you, and it will typically save you money in the long run. In a large organization, this might include involving those who have specialized training. Every large organization should have mechanisms in place for people to request and help as well as report problems. It is very useful to know what that process is before a problem occurs, so that in time of need, you can quickly reach out for assistance.

When all is said and done, sit back and consider what happened, making mental notes on what not to do in the future. Spread the word: educate your colleagues, friends, and acquaintances.