Admin Problems after installing Lion

A few years ago, on a 1 week old iMac, I had a similar problem that you had with your trash can.

I just lived with it for a few weeks. I knew Leopard was being released soon and the people at the Apple store told me to just bring in the iMac and they would install Leopard on it at no charge.

They installed Leopard and there were so many odd bugs when testing it, they ran diagnostics on the iMac. It turned out the hard disk was defective and they ended up giving me a new iMac.

 

The first, and easiest, possible fix is to boot from the disk that cam with your computer and run Disk Utility, and use the repair permissions feature. That might fix some of your problems.

I believe the group wheel on a Mac includes all administators, and you seem to say you're logged in but in the group everyone with only read permission.

Are you logged on to the Mac in your administrator account?

 

I think I'm having a related issue. I can't seem to unlock certain options in System Preferences. Such as Login Options. I authenticate, hit OK, and nothing happens.