CAN YOU HELP?? (This is a long one, but please be patient and read it through before answering)

Question

Basically, I screwed up my MAC in the terminal a few months ago. I don't know what I did, but it basically started erasing all the documents, data, bookmarks, extensions, literally everything from my desktop too. And I could not undo this.
Although, when I first got my laptop, I thought it would be a good idea to have different user accounts for different things (i.e. one user account for my personal life, one for professional life, one for school, etc). So after my documents and data and everything on my desktop started disappearing, I feared the worst and thought I messed up my entire laptop. Thankfully the entire hard drive wasn't affected---only one user account (called ALEX) was.
So instead of wiping the mac clean and having to start over (because I would lose all the data from my other user accounts), I decided to make another separate user account to replace the messed up one with. I named this new account "MARS" and made sure to set up the account as an administrator (just like all my other user accounts, save for the Guest account, of course) with all the permissions to make admin changes.
While still in the ALEX (messed up) account, and after searching forever online, I found that there was a way to change permissions of documents or even folders if they are moved into the "Shared" folder of another user account. Doing this would overwrite the permissions of that folder and all the sub-folders inside. I had a backup of the ALEX account on a Seagate Drive that had most of my itunes music (which is really the only thing I've been trying to get back--that and my bookmarks and chrome extensions), but I found that I couldn't simply backup one user account through time machine--I can only backup an entire computer hard drive.
Still in the ALEX account, I figured that I could instead solve my problem by transferring the documents and data from the ALEX BACKUP user account to the shared folder in the newly created MARS account, thus overwriting the permissions and getting all my old files back (all my old chrome extensions, documents, pictures, itunes music and movies, desktop, etc), now on the new account.  Just one problem: I couldn't seem to open the new MARS user account (by going to Finder > Macintosh H.D. > Users > MARS) and thus, could not even get to the public folder and move the ALEX BACKUP files into the drop box at least.
So I switched users, logging into the new MARS account. I opened the Finder window, selected my Macintosh H.D., and opened the Get Info window for the hard drive. I went down to sharing and permissions, unlocked the little padlock to make permission changes, and added all admin users. I then proceeded to change the sharing and permissions to "read & write" for all admins, and selected "apply to enclosed folders" in the little gearbox settings icon (this is all in Get Info). It worked, and I was able to open all the folders from all of my user accounts, but now I couldn't open my own Home folder (the MARS folder in Users that is a picture of a little house), which was baffling to me because I was already logged into the MARS account.
Then I noticed a little padlock on my home folder (remember that I'm still actively in the MARS account), and also noticed that the Seagate external hard drive I had plugged in (which serves as a giant usb and a time machine backup disk) had the same little padlock. Now when I try to open the user account folder for MARS (either while logged into the MARS account, or logged into any other admin account) or if I try to open the external hard drive, I get this message that says "The folder can't be opened because you don't have permission to see it's contents."
So now, I can access all my user accounts from anywhere, but I can't access the new MARS account or my external hard drive anymore. So next problem on my list is solving the external hard drive issue. First I went into the Get Info window for the external hard drive, and tried to change the permissions there by unlocking Sharing and Permiss., and changing the settings for each user. Only all the users listed were set to "Custom" and even worse, every time I tried to change it, it automatically bounced back and reverted to "Custom." There was a little check box on the bottom that said "Ignore ownership on this volume" so I tried checking that box and doing the same thing. Also tried simply checking and unchecking the box. Still no luck.
Time for plan B: I went into disk utility and selected the external hard drive, then went to the First Aid tab. There were four options I could chose from: Verify Disk and Repair Disk (on the right), and Verify Disk Permissions and Repair Disk Permissions (on the left). First I immediately verified and repaired the disk and it said "The drive appears to be ok" after the repair was done. Then I tried to verify and repair the disk permissions, but I can't click on either Verify Disk Permiss. or Repair Disk Permiss. They are both greyed out and unclickable.
THIS is where I drew a line in the freakin' sand, did NOT read the Latin**, and decided to write this long-*** post in an attempt to find some kind of answer to my dilemma. So if anyone reading hasn't given up and you've reached this sentence with some kind of suggestion in mind, I would extremely appreciate any help I could possibly receive. I've been trying to deal with this situation for months now. Unfortunately my year of Apple Care has expired and I can't talk to any Geniuses in store on the matter, so if the internet is willing enough to help me, I promise to spend more time with it. Maybe even go back to MySpace. ****, I'll start using Google Plus if it means finding an answer. (You see the desperate lengths I'm willing to go to on this.)
**This is a reference to "Cabin In the Woods," when they're in the basement reading Patience's diary. Then there's a line written in Latin that basically brings zombie-redneck-torture-families back to life. Marty, who's been desperately trying to get them all to just go back upstairs, stops them and says, "Okay, I'm drawin' a line in the f*ckin' sand here; DO NOT READ THE LATIN." If you haven't seen "Cabin In the Woods," I definitely recommend it--it's a hilariously terrific thriller and even Sigourney Weaver shows up at the end.
Anyways if there's anyone out there who can help me, please!! (I've even got legendary weapons in Borderlands 2 I'd be willing to dupe as payment!!)
Please leave a reply, if you can. Or send me a message (not sure how this forum works, as I'm a little new to the forum).
And also, if your answer includes going into the terminal, I can tell you right now that I'll probably be extremely hesitant to go that route (seeing as trying to fix a problem using Terminal is what landed me in this entire mess, in the first place).
I really look forward to any help I can get. And thanks so much guys, you really make the mac community thrive by helping people out like this!

Answer 1

I'd still prefer to keep separate user accounts. I never had any issues like this before. The only time I started having a problem was when I was just trying to force empty the trash a few months ago. I came on here looking for a solution and someone posted a way to empty the trash using the terminal. Before then, I hadn't used the terminal for anything--it was just another app in my utilities folder.  (None of this has anything to do with having separate user accounts. Plenty of people with kids make second and third user accounts on their laptops so that multiple people can use one laptop, having more than one user on a laptop is not very difficult.) But thank you, I'll try that out and see if it works!