Computers become bogged down over time with a lot of data they don't need, such as programs, videos and Internet files. This will inevitably cause the computer to run more slowly and less reliably. You can go through your files to clean out files and programs you no longer use. Additionally, maintenance tools can be used to speed up your computer.
Uninstall any programs you don't need by accessing your list of installed programs via Windows' Control Panel. Access your programs list by clicking "Start," clicking "Control Panel" and selecting "Programs." From here, open "Programs and Features." Select any program from the list, then click "Uninstall." If you aren't sure exactly what a program is, don't uninstall it; many integral applications are listed there, and could disrupt your computer's operations if removed.
Search through all of your files and remove what you don't need. Look through the folders you most commonly save files to, such as your desktop, "My Documents" or "Downloads." Over time you may have picked up some duplicate files, or have a number of large files you didn't even remember saving. The fewer files on your computer, the more hard drive space you have, and the less your computer has to index for search results.
Run "Disk Cleanup," a built-in maintenance utility. Open your programs list from the "Start" menu, open the "Accessories" folder, and open the "System Tools" subfolder to find it. Run this utility to free up more space on your hard drive, clear out temporary Internet files and speed up operation. "Disk Cleanup" scans your computer for any data it can safely delete, which are often files that sit on your hard drive without doing anything for long periods of time. It also compresses whatever data it can to save space.
Open "Disk Defragmenter" from the same folder you found "Disk Cleanup." Run it by selecting your main hard drive -- usually the "C" drive -- then clicking "Defragment." This program searches for fragmented files to put back together; it may take over an hour to run completely if you haven't used it before. Putting fragmented files back together means your computer will have to use less processor power to perform the same tasks since it won't be searching multiple locations for one item.
Clean out the dust from your laptop or desktop tower using a can of compressed air. Shut down your computer completely, open the tower to expose the internal hardware and use the can to blow out any dust from the inside. If you're using a laptop, you can still clean out the fans and under the keyboard. A buildup of dust can cause your computer to retain heat, which can cause it to run slower (and louder) and potentially cause damage by overheating.
Programs take up space on your hard drive and potentially take up RAM as well if they are active. Remove anything you don't need or want anymore to free up some space, then restart your computer, as some programs may require a restart to complete.