Sounds like you installed it for standard users, you use a standard user account and you changed something while you were logged on as an admin. If you did anything as an admin to make a file Flash writes (configs, etc) then they can become unable to be utilized again by anything other than the administrator.
As administrator, you can right-click on a folder, open up properties, use the security tab, advanced at bottom, owner tab at top, edit button, select your username, check "Replace owner on all subcontainers and objects" then apply and keep hitting apply/ok. That will reset ownership of all the files back to the user you designate which shouldn't require administrator privs.
Additionally, as administraotor, you can go in properties->security tab->edit button, select your user and make sure they have full control permissions.
I'm not even sure how to log in as administrator, but when I right-click on Flash.exe and select properties, then security, it shows Users (computername\Users) have Full Control permissions.
That's just one file. If you didn't explicitly make an admin user then you ARE the administrator.
Forget about logging in as Administrator and just do the same process to set the "owner" of the whole folder to yourself, incase something weird happened.