A slow computer is frustrating, but in most cases the cause is identifiable and fixable. Before you assume you need a new machine, work through these steps. Many computers run significantly faster after a few targeted changes.
Too many programs launching at startup is one of the most common causes of a slow boot and sluggish performance. Press Ctrl+Shift+Escape to open Task Manager, click the Startup apps tab, and disable anything you do not need to launch automatically. Right-click and select Disable.
In Task Manager, click the Processes tab and sort by CPU or Memory. If a single process is consuming an unusual amount of resources, that is your problem. Look up the process name if you do not recognize it.
A failing hard drive slows everything down dramatically. Search for Windows Security in the Start menu, go to Device performance and health, and check the Storage capacity section. For a more detailed check, search for Optimize Drives and run a scan on your drive.
Windows needs free space to operate. If your drive is more than 85 percent full, performance suffers. Open Settings, go to System, then Storage, to see how much free space you have and what is using it.
Malware running in the background is a common cause of sudden slowdowns. Open Windows Security and run a full scan. If Windows Security is itself not running properly, that is a sign of a more serious infection.
If your computer has less than 8GB of RAM or is still running on a traditional spinning hard drive, upgrading either one is the single most impactful hardware change you can make. An SSD in particular makes an old computer feel dramatically faster.