I think I messed up my OS file security?

I started having problems, maybe just perceived, a while back.  After doing a FSX reinstall I started finding myself locked out of making changes to a few files. ie: FSX.cfg, EXE.xml and SaiFlightSimX.xml.  Seems there were a few others.

Anyhow I looked at their properties and saw they were read only?  I am the admin and have never had a problem with them before.  So I attempted to change the attributes but was denied by the OS?  Curious, I don't recall anything like this before.

So, being very late one night, I went to C: and gave everyone full permissions in properties\security of C:\.  Well, that worked very well; except it appears I gave everyone authority!  I only meant to give it to me?  So I made another change, I only wish I remembered what it was. 

So now I do have the authority but instead of getting messages like " are you sure you want to delete this program or configuration file?" it just deletes them when I press the delete key if I am in a directory.  I use 2 systems with 2 keyboards and sometimes I key something on the wrong one.  You see where this leading?  I am afraid I will accidentally delete a file by mistake and not know until some later date that something isn't working anymore with no idea how or why.  I have caught myself, 2 times yesterday, doing exactly what I described and undid the deletions right away.

I know, be careful but I am prone to irrational moments, I have O.L.D. really bad, as my wife points out (on a regular basis I might add). 

Anyone got any idea what I did and or how to fix it?  UAC is off.

I feel like I am walking around with a loaded gun in my hand, a hair trigger, no safety and my finger glued to the trigger.

Thanks

Rick S.