In case your PC does not have Storage Sense, you can use Disk Cleanup to free up space in your system.
Here is how you can use it:
Step 1: Go to the taskbar. In the search bar, type Disk Cleanup and then select the corresponding result.
Step 2: You will see a list of all your files here. You can select the ones that you want to delete. The Downloaded Program Files, Temporary Internet Files, and Thumbnails are automatically selected for removal. If you do not want to delete these, you can uncheck the boxes.
Step 3: You can go to Clean up system files to free up additional space in your system. It will take a few moments for Disk Cleanup to estimate the amount of space that this step will help clear up.
Step 4: Now, you can select the files that you wish to delete. When that is done, simply click on OK and then Delete Files. This will give confirmation, and the cleanup will begin.
If even after cleaning up, your computer is running slow, you can try uninstalling the apps that you do not need and use anymore.
Here is how you can uninstall the apps:
Step 1: Click on the Start button. Go to Settings > Apps > Apps & Features.
Step 2: If you have a particular app in mind that you do not need, you can search for it. You can also choose the app from the list there. Once you have selected, you can proceed by clicking on Uninstall.
Step 3: When the uninstallation is complete, you need to restart your PC to see if there is any improvement in performance.
If you feel like there is no change in the performance and your PC is still lagging, you can try moving photos and music to removable media. You can connect the media to your PC when you need access to them, but since they will not be stored in the system anymore, they will not take up space.
Here is how you can move your files:
Step 1: Connect a removable media to your system, for instance, a USB drive.
Step 2: Go to File Explorer and look for the files that you would want to move to the USB drive.
Step 3: Select all these files. Go to Home > Move to > Choose the location.
Step 4: From the list of locations, choose your USB drive or any other removable drive that you are using. Then, select Move.
Step 5: Restart your PC after this step to see if there is any improvement in performance.