Ultimately, it's up to you to decide which programs get dumped at startup. As a general guide, don't disable stuff that works in the background, comes from a component maker like Intel or your PC manufacturer, or is a mission critical app such as antivirus.
The first thing a Windows 7 user should do is click Start > Startup and see what's there. This folder houses all the third-party apps that activate at start-up. If you see anything you don't want right-click it and select Delete.
Another option is to get a window similar to what Windows 8.1 users see via the Windows System Configuration Utility. The name alone sounds scary, so if you are not comfortable with this step, don't sweat it. Just download a program like the ones mentioned at the top of this post to clean up your PC for you.
For those brave enough to sally forth, click Start > Run and type msconfig in the box that appears. Once the configuration utility starts up look under the Startup tab.
Unlike Windows 8.1, Windows 7's approach is far less friendly to look at and doesn't include any helpful startup impact information. This is really a window for more advanced users. However, if you find programs like Google Chrome, QuickTime, and Skype in the list, feel free to disable those by unchecking the box next to their names.
One thing I would not recommend disabling if you often connect an Apple device with your PC is Apple's "iTunes Helper." If you disable this, it won't turn on by itself and can lead to hassles every time you want to sync a device with iTunes.
It can take a few minutes to figure out which programs should be disabled on your PC. If you take the time, the benefit of shaving those few extra seconds off your boot time is worth it.
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