For example, I'm using the latest Skype 6 here, and after opening Skype, I click on "Tools" in the upper left corner, select "Options", then on the "General settings" tab, I UNCHECK the box next to "Start Skype when I start Windows".

As to other items you which to disable at startup, try the settings in those programs as well.. If no such settings exist, then click on "Start-Run", then type "msconfig" (without the quotes) and click on OK. When the System Configuration Utility loads, click on the "Startup" tab.. Once there, UNCHECK those items which you don't want starting up when Windows loads.. (It's generally best to leave drivers and security programs alone in this area.) Once you're finished UNCHECKING items, click on "apply", then OK and let the computer restart.. Upon restart, you'll see a warning window about System Configuration Utility..So, place a CHECK mark in the box which prevents it from popping up again at startup.

Of course, if you don't want a program on your computer at all, simply uninstall it from the Control Panel-Add/Remove Programs section.

Hope this helps.