A slow computer often crashes because Windows is using significant system resources to read and write to the disk. When you open Task Manager and see 100% disk usage, stopping the process that is forcing that usage will get Windows back to normal.

There are several possible causes for high disk usage in Windows 10, but most of them boil down to the same idea: too many things are being run by your computer at once.

A common cause is swapping or paging. Swapping occurs when a computer runs out of physical memory (RAM) and needs more space to store information about its running processes and applications. It uses a file on the hard drive called swapfile.sys to hold it. As Windows works with that information, it is constantly reading and writing to swapfile.sys, which drives up disk usage.

You will also notice that applications that search through or use many files at once will access the hard drive behind the scenes at an alarming rate. Many applications can behave this way, including antivirus software and some utilities that come installed with Windows.