I said the system tray was packed. That's the space on the bottom right hand side of the screen (although I've no idea if it's still there on Windows 7). Each icon there represents a program, running in the background, that took time to load at startup and is using memory and CPU cycles. I've noticed on many machines, particularly laptops, that it is often full of programs the owners have no real knowledge of and in many cases have no actual use for. It just seemed like a good idea when they installed it, or the computer came with them already installed.
Windows is also designed (although maybe "evolved" is more accurate) rather differently than *nix OSes, like Ubuntu, and some of these differences, like having a centralised registry, make it very easy for 3rd party software to affect the running of the system when really they shouldn't be able to.
Geeks have been saying for years that the designers should sort Windows out, sometimes very impolitely. However it's so complex that this is no small task, and almost certainly not a profitable one. It's much easier to pop some eye candy on and tell people to buy a faster computer
Anyway, I'll bow out from this as I don't want to start an OS holy war (there are far too many on the web already!). For the record, I do use Windows but it, like all operating systems, requires some care and attention to keep it at its best.