You won't corrupt your friends compute. this is 100% harmless, I promise! 
Go into the backup folder, right click the file inside and select "Copy" and go back to your Saved games folder (Click on My Computer > Click "OS C:\ then click the User Folder, Click on The Username you use when you log in to your PC, Then Click on saved games, then once more on the Pokemon Uranium Folder. Right click and select "Paste". Your computer will ask you if you want to overwrite the old file, select yes 
Go into the backup folder, right click the file inside and select "Copy" and go back to your Saved games folder (Click on My Computer > Click "OS C:\ then click the User Folder, Click on The Username you use when you log in to your PC, Then Click on saved games, then once more on the Pokemon Uranium Folder. Right click and select "Paste". Your computer will ask you if you want to overwrite the old file, select yes
Backup your saves, don't lose progress!
C:\users\<Username>\Saved Games\Pokemon_Uranium
Save Backups:
C:\users\<Username>\Saved Games\Pokemon_Uranium\Backups
C:\users\<Username>\Saved Games\Pokemon_Uranium
Save Backups:
C:\users\<Username>\Saved Games\Pokemon_Uranium\Backups
OID: 000003 OT: Cody
