You're never going to use the borked trial versions of all these programs that came pre-installed on your new laptop or smartphone, so why should they continue taking up precious hard drive space? Here's how to cut the deadweight out of your operating system.
Bloatware is installed your device for the manufacturer's benefit (read: cash money), not yours. These programs, often a trial version or other hobbled iteration, are essentially paid advertisements by software developers to get you to buy the full program. Paid ads that can compete with your preferred programs, slow system performance and generally take the fun out of getting a new device. Luckily, there are plenty of simple solutions to removing them.
To get both of the pre-installed Norton and McAfee programs competing with your preferred installed AVG off of your system, you've got a couple of options. You can always uninstall them individually from the Programs manager in the Control Panel. To do this, click the start menu in Windows 7 -> Control Panel -> Uninstall Programs. Then work your way through the list of installed programs, uninstalling them as you go. But, since most new PCs come with a lot more than two bloat programs (it's closer to a dozen), removing each individually can forever.
On the other hand, you could go the opposite route by wiping the drive and reinstalling a clean build of Windows using a store-bought copy. To do so, first backup your drive. Then insert a store-bought Windows install disk and reboot the system (or run the downloaded copy you bought from the Microsoft store). From here, simply follow the install wizard and the onscreen guide (it's pretty intuitive, but you can head here for a fairly comprehensive walkthrough). But this will cost you both an afternoon and extra cash for the clean OS copy, which is a bit of a kick in the face seeing as how you just ponied up for the laptop itself.
There is a third option, however: CCleaner. This mass uninstall program is built to clear the crap from your computer with minimal hassle. Simply install and run it. Choose the programs you want to get rid of from the menu and let CCleaner do its thing. Obviously you'll want to get rid of all the Demo and Trial programs, but also keep an eye out for third-party media programs, antivirus suites, and anything else that you don't need. Once it's run its course, restart your PC and restart CCleaner. Run it once again to clean up the system registry and you're ready to start installing your own programs.
Your latest Google OS handset is no stranger to bloatware. These programs do little more than take up storage space (hundreds of megabytes on the Galaxy S4) and demand full system access (which is for totally noble reasons, I'm sure) but they can be removed with a bit of work.
Since most pre-installed Android programs will allow you to either disable or freeze their functionality but will not allow you to uninstall them outright, you'll need to take more aggressive measures. Like installing a fresh copy of Windows on the PC, your primary nuclear option is to install a custom ROM. By doing so, you'll also eliminate the bloatware; however, this method takes a bit of technical know-how and isn't right for everyone. If you do decide to go that route, however, Cyanogenmod is a popular, customised, open-source ROM.
The install process is somewhat akin to the PC wipe and reload, but each ROM is designed for its specific phone model — the ROM for an HTC One won't work on a Galaxy S4 — so be sure you use the correct one. The Cyanogenmod Support wiki is an invaluable source of information regarding the installation process, so be sure to read through it a few times before you start hacking your pocket computer. You could also root your phone and forcibly delete the offending programs, but this too should be reserved for those sufficiently proficient.
Perhaps the easiest method, though requires little more than some intelligent cutting and pasting. XDA Developers member Broadways have assembled this slick little bloatware removal script (.zip) that will delete the programs without needing a root. Be cautious though; delete the wrong program and you'll brick your phone. Head over to the XDA Developers forums for a full set of instructions.