I don't know how to change the theme of my computer (on vista) to windows aero? Help?

I've got Vista Ultimate.



I deleted Vista Visual Manager, and then i clicked Windows Classic theme when the manager came up.



I don't know why i did that, but know i can't access my original theme, its changed to the classic.



And then, when i try changing the theme, i browse into C-%26gt;WINDOWS-%26gt;RESOURCES-%26gt;THEMES, and i click Aero, but then a prompt pops up saying the file cant be read.



How can i change this?



- Please bear in mind that i want this change to be permanent.I don't know how to change the theme of my computer (on vista) to windows aero? Help?
When you right-click on your desktop and go to ';Personalize';, do you see ';colors %26amp; appearances'; option? If you click that, it should display vista standard/basic, after which you may be able to revert it to full-fledged aero.