A program that enables a person to control a computer through the internet or other source.
It consistes of two parts, the client and the server. The client is the control center that controls the other computer. The server is the part that loads on to the computer controlling.
Get a virus scanner and update every so often to scan files you download from the internet or disks.
You could also get a firewall if you are enable to get a anti-virus program. This will allow you to judge who can communicate with your computer.
Goto your win.ini file and see if any abnormal files are becide 'load' under '[windows]'.
Be sure to press 'end' on that line to see if it is just spaced out.