Read Only Attribute applied to my external, cmd = 'access denied'

This just happened in the last week. I have an external hard drive where I keep all my data. Suddenly I am now unable to save, move, delete, etc. I am administrator as well as owner of the files that are being affected...everything on my external. I do not know how or why this read only attribute got applied to my J: drive but I have tried everything that I've read in your forum and I dont know what else to do.
Why would the computer apply read only to an external? It wasn't there last week, I've never had this problem. I first tried the windows route to change permissions and such, failed, then i used the elevated command prompt and attrib variations that should have corrected the situation, failed. The last thing I got before i was forced to quit trying for the moment is when i applied the attrib cmds to all subfiles and folders; at first it said something about hidden files so i placed the -H in front and suddenly the screen was filling with all of the file on the external, but saying that it could not access the files.....bottom line is that i got down as far as i've been able to figure out by reading the posts here and the last thing that happened was that it finally was able to get to the files but came back with "access denied" on every file and folderl
Can anyone think of why this could happen to an external and if there is some way to repair it? I have already tried copy/paste into another location yet still the read only square is there.
Please help. Thank you;

Thank you for responding, but I am the owner of the drive. I had to do that previously during a little mix up between me and the computer; you see the computer wanted to be in control, i decided to tell it "bad dog" and took ownership.
But this is different, it's like the System folders attributes have been applied to my external and I can't comprehend how that could happen. I have tried using command prompt and failed. the read only status remains. If this means anything, it says Read Only (only applies to folders and files inside this folder) or something thereabouts, suggesting that it doesn't apply to the actual folder. I see nowhere on the actual drive where it can be made read only, just the first folders inside the drive, which then affects everything beneath.
And because it's read only, my malware and antivirus are unable to to anything so they don't even scan the drive anymore.
There is another thing, I don't know much about sharing, but the external drive says "Not Shared", could that have something to do with it:
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Thank you, and please advise, anyone. Oh, and I could not get that "Take Ownership" on the right mouse button to work for me, I must be missing something cuz it never turned on.

Thank you so much Brink, I very much appreciate your assistance. I knew next to nothing about permissions and sharing, but once you put me on the right track it was tedious, but easy to find that my main admin didn't have share rights even though he was administrator and owner...l.i still don't understand why owner and administrator don't over ride sharing and permissions, but the issue is resolved thanks to you. Now that my main admin has full sharing and full control he was able to see to it that the other admins were set properly as well. 'Even my little Standard User, whom I use for regular uses, has been included a bit better and he likes it lol

Also, my security programs, antivirus and malwarebytes, are now able to access the network drive agqain. I thought to bring SYSTEM on board and give it share and permission rights. I was assuming that SYSTEM is responsible for running programs like these so I went on a hunch and sure enough, my external drive is now being included int the scans once again.

Well, thank you again Brinnk, and take care

Luke