Is there a way to tell if someone is hacking into your computer and?

Can I have a little more information. Like what your computer is doing or why you think you are being hacked. I am an IT Manager and can probably help you figure it out, but I need to know what your computer is doing. If you are concerned about trojans or spyware, I would suggest you go to http://www.bitdefender.com. They have an online scanning tool that will find and remove threats.