File Permission Settings for External Drive

I think I've screwed myself up into a corner. I really need help as Google is not bringing up anything that might help.
What happened is I tried to adjust the security setting for my whole external hard disk.
I have the admin rights to my computer and wanted to restrict a user to be able to read and execute only. I right clicked the drive (L:\) and adjusted the EVERYONE group.
What I didn't know was EVERYONE included the admin too. So now I've blocked myself from editing the files and folders in the external. Now I see all accounts have the special permission part unticked.


And if I check the properties of a folder in the hard disk I see an account with the special permission allowed


In a fit of panic I accidentally removed the account with special permission privilege from my hard disk properties so I don't see it when I check the properties of my hard disk but I can see the account when I check the properties for the individual folders.
For awhile I had access denied when I tried to enter the drive but now I can enter but still am restricted (can't delete folders, etc)

How do I rectify this mess I'm in?

Through further googling, I've discovered 'taking ownership' so it's all settled now.
Admins, you can close this thread

No problem! By further googling I meant looking at the similar threads links at the bottom of my thread so technically someone did help.
Anyways I'm just glad to get my hard disk back