A: Yes, you can turn off User Account Control (UAC), but I don't recommend you to do so because it weakens the overall security posture of your Windows system by giving more opportunities for malware to get installed and do harm on your system.
To turn UAC off in Windows 7, type UAC in the Start menu search box to bring up a link named Change User Account Control settings. Click this link to open the User Account Control Settings dialog box, then drag the slider all the way down to the bottom to disable UAC entirely -- as Figure 1 shows.
Figure 1: Turning off UAC in the User Account Control Settings dialog box (Click image for larger view)
To turn UAC off in Windows Vista, type UAC in the Start menu search box to bring up a link for Turn User Account Control (UAC) on or off. Click this link, then on the resulting screen, clear the check box for Use User Account Control (UAC). Click the OK button. Both on Windows 7 and Vista, you'll need to reboot your system before the changes take effect.
Microsoft also provides Windows Group Policy Objects (GPOs) settings to let administrators change and fine-tune the default UAC prompt behavior for limited-account and privileged-account users. You can find the UAC-related GPO configuration settings, which start with the words User Account Control, in the \Security Settings\Local Policies\Security Options GPO container.