Why Is My Disk Usage Constantly at 100%, and Would an SSD Fix the Freezing?

Some people have reduced heavy disk activity by disabling the SysMain service, but I would treat that as a troubleshooting experiment rather than the main solution. First identify the process causing the usage and check the drive's health. If the disk is constantly busy even when nothing obvious is running, replacing the hard drive with an SSD is a sensible next step.

An SSD would probably make the system feel much more responsive, especially if Windows is constantly swapping data or loading files. However, 100% disk usage by itself does not prove the drive is the problem. Open Task Manager and check which process is using the disk. Background updates, antivirus scans, a failing drive, or another program could be responsible. Since you have roughly 16 GB of RAM, insufficient memory is less likely, though a memory test is still worth running if apps are freezing.

Before buying anything, check whether Windows or another application is downloading updates or performing a scan in the background. Also check the hard drive's health and run a memory diagnostic. If the drive is old or showing errors, replace it and make sure important files are backed up first. An SSD is a worthwhile upgrade, but it will not fix rogue software or faulty memory.

A practical upgrade would be to install a 500 GB or 1 TB SSD, depending on how much space you currently use. You can either clone the existing system to it or perform a fresh operating-system installation and keep the old drive for extra storage. A fresh install is often simpler if the current drive is cluttered or unstable. Defragmenting may help a little with a traditional hard drive, but it will not solve a hardware failure.