How do you tell if your computer is being accessed remotely?

If it is running slower than usual, usually says if your are being monitored or not. If you think it is spyware, run a full computer scan with something like norton. If you think you are being monitored over a network, check how much data your computer is transferring by using task manager (CTRL+SHIFT+ESC) and clicking on the network tab. If you are not downloading any files or using the internet and the graph shows above 5% for more than a few seconds you might be being monitored