@Bod, AC, Antidis... et al
billy is mostly correct. You'd know it if you had ever run a modern Linux distro. You're taking his words and screwing them up to imply that it is hard to install new programs or to work with a Linux system. That is totally incorrect. When an authorized user is sitting at the machine and logged in, installations are as smooth as they are on Windows ... maybe smoother, because most modern distros check whether the software will work with the system before installing, which Windows still cannot do. For most modern programs, you simply download or insert the install disc, double-click the icon and ... voila.
The difference is that when an UNauthorized user tries to install something on the system, such as one of the malware currently making the rounds, then (1) if it is authorized by the local user, then that's the only portion of the system that it can harm ... it can't kill the whole machine (including ROM/CPU) that a Windows nasty can, and (2) it will not automatically execute when the drive/media are plugged in, unlike under Windows.
If you're saying, "Well I don't have to even open the CD in Windows, it plays it as soon as I put the disc in", then you're completely missing the problem ... which is exactly that behavior.
Head out of butt ... get yourselves some experience with Linux before you post silliness like that again, please.