If you think that your system has somehow managed to be infiltrated by a worm or some other little spyware utility, Task Manager is the best place to start searching for answers. While the little buggers typically won’t appear on the Applications tab, it’s very difficult for them not to appear on the Processes tab. This is where your investigation should begin.
If you do think you’ve got a critter running in the background, start off by exiting all applications in your system tray. From there, start looking for names that appear suspicious, or those than seem to be consuming very little resources. Since the name generally won’t jump out at you, search for the full process name in the Process Library or Google, and see whether it’s valid for your system or not. Sometimes you’ll find that what you think looks suspicious is actually an operating system process, or some other valid program you installed. However, if the process is spyware or similar, chances are good that it will be obvious on the first page of Google results. Task Manager can help you identify the process and end the process, but you’ll need to sort the details of deleting it permanently. Happy hunting.