No entry sign on files

Hi, maybe you can help,

I previously backed up my computer and found that the backup files were invisible. I thought this was connected to hard drive issues I was having, but have now discovered that the backup files were invisible because I had renamed my computer using non-alphabetic figures only.

I changed the name of my computer and did another back-up on the drive where the invisible files are located. The previously invisible files are all visible now.
But, problem now is that they have a no entry sign on them because they were backed up before I reformatted the hard drive. When I did that I had to create a new user account, which does not give me access to the old name/ account on the backups.

Any ideas how to get round this?

Thanks!

If you have an admin account you should be able to right click on the containing folder and select get info

At the bottom should be a privileges and permissions tab, unlock it and provide your admin password.

Select read write privileges for your account and from the gear icon at the bottom select apply to all enclosing items

That should give you access to all the containing files and folders