Hi, someone has added two suggestive Icons on my desktop and I'm 100% sure they came from an intruder. That something would be done to my pc has even subtly been pronounced by users at a website I have visited. I didn't believe someone would be capable doing something like this, since I have a security program, but now I'm stunnend. How can I find out who this intruder is and how can I get rid of him?
There are a number of things to check for before you can begin to say you are 100% sure it's an intruder. It is possible, but first, try the following: Scan your system for open ports when you boot into it.(you can use Nmap: http://www.nmap.org/ Record the open ports to your system. The only way the intruder got access to your system is through one of these ports. If you have any suspicion on any of the ports, then you can begin to believe it's an intruder. The reason I say this is because any "smart" intruder knows how to "cover his tracks!" Therefore I don't think he would let the icons on your desktop seeing you would realize he was (or is) there. Do that for a start and post the result.
Along with scanning your ports I would also suggest beefing up security on your system. There are two great firewalls that come to mind, one is zone alarm pro and the other is hotspot shield. Zone Alarm is a top of the line firewall which does consume some system resources while hotspot shield is lightweight but still shuts down 99% of intruders out there (and it's free).