A lot of programs register themselves to run when Windows starts. This can be extremely annoying as you go on and it can reach a ridiculous point if you are not careful. This is very common with people that also agree to everything in installers and end up with 10 brilliant toolbars in their browsers. Although you can usually disable this manually in each program’s settings menu, you can also do see a list of startup items (including things like software update helpers) and disable them from running automatically. Although this might seem like a small thing, it can actually boost the performance of your computer, especially in the long run.
Press the WinKey, type in msconfig and press Enter. Navigate to the Startup tab and disable whatever you do not want to keep in there. After you click on OK, you will be informed that you need to restart the computer in order for the changes to take effect. You can obviously do it right then and there but waiting until later is absolutely fine.
Things are far easier in the latest version of Windows. Press Ctrl + Shift + Esc to bring up the Task Manager, click on More Details and go to the Startup tab. Here you will be able to see all the services like you would in msconfig.
Some third party utilities, like the brilliant CCleaner offer more in-depth Startup editing utilities. As I have already used CCleaner as an example, it can also pick up startup items for browsers and offer a more rounded manager that you can use to really manage any item that might pop up during boot. If you have not done so already, be sure to download the utility from the provided link.