Hi Hugo,

PC Reviver and Disk Reviver are both different programs and have different features.

PC Reviver is a multi-purpose utility that will diagnose errors on your PC, safely repair them, and provide other maintenance and optimization recommendations.
PC Reviver is the trusted and recommended way to restore optimum performance and stability to your PC.

Disk Reviver will scan your hard drive for performance improvements. Disk Reviver can quickly and safely clean junk files, optimize your hard drive and maintain your hard drive health. The result is a faster, more reliable hard drive that is crucial for the functioning of your computer.
Disk Reviver can clean junk files, temporary files, and other unnecessary data saving you valuable disk space and improving performance. It also helps you identify and remove duplicate files on your computer to recover more free space.

For more details, please see below link for both the programs:

PC Reviver

Disk Reviver

I hope this helps.

Regards,
Lokesh