The c:\System Volume Information folder is a part of the system restore function and as such is protected by windows, the only way to clean infected _restore points is to disable system restore and reboot. This will clear ALL _restore points. Once you have disabled system restore, reboot, scan your PC again and if clear enable system restore.
So the purpose of the _restore points is if you experience a problem on your system you can take a step back in time to see if that resolves it. Files deleted previously from system folders are saved as restore points just in case you made an error. These could have been previously deleted viruses, we can’t tell that as there is no file name in your information.
Deletion isn’t really a good first option (you have none left), ‘first do no harm’ don’t delete, send virus to the chest and investigate.
I haven’t got a clue what won’t work as there isn’t enough information, but files in the c:\System Volume Information folder should have zero immediate effect as they aren’t in use but backup. Clearing ALL restore points as outline above wont harm anything it just means you don’t have those restore points to go back to, not good if they are infected.