Here are instructions to disable UAC:

http://www.vistaclues.com/how-to-dis...count-control/

UAC is a good thing, though, and will help keep you safe from spyware and
viruses. Try turning off the secure desktop first and see if that's good
enough for you (it makes UAC less annoying):

http://www.vistaclues.com/make-user-...less-annoying/