Non-system processes like searchindexer.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues.
In order to ensure your files and data are not lost, be sure to back up your files online. Using a cloud backup service will allow you to safely secure all your digital files. This will also enable you to access any of your files, at any time, on any device.