A. In the past few weeks I've seen an increase in the number of computers for whom the control panel is not available. In addition, you can't execute "regedit", "control userpasswords2", or right-click My Computer > Properties. All attempts result in an error stating the action requires admin rights and it's been disallowed for you.
This is a result of the Zlob family of viruses. It's a particularly nasty family of viruses that takes quite a few steps to resolve.
First step is to gain control of your registry so it can be modified. Since you can't run "regedit" to modify it manually, you'll have to get some software.
Before doing the steps in the cleaning as outline, disable System Restore. This will delete the SR files, which can't be cleaned by these utilities but if they're infected, you'll keep getting problems.
When finished the cleaning, update your antivirus definitions, and run a full system scan.
Download, install, update, run Ad-aware, Spybot Search and Destroy, Spyware Blaster.
That should get you cleaned up.