Grr, ur all nubs.

A backdoor trojan just basically opens ports on ur pc therefore making it vunerable to anyone trying to connect to your pc through that port and in essance they can have complete remote control over your pc.

I had some great times with backdoors, flipping my friends screens upside down, making their cd tray go in and out loads times, making the caps lock num lock buttons flash etc, locking thier keyboard and mouse and typing funny things in notepad infront of thier eyes an theres nothnig they can do about it.

Also it means you have access to any file on that computer, and can delete it.../you can execute any line of code.

Not so great.

What i advise you do, is if ur are a pr0 h4x0r like me, u close the port, if not, get yourself a good firewall (I reckomend Zone Alarm, norton and windows built in firewalls wont do).

Easy. Fixed.

Hope i helped.