To disable UAC in Windows 8 Professional:
From the Desktop, press Windows Key + R to access the RUN dialogue. Type 'GPEdit.msc' into the form and click 'OK'.
In the Local Group Policy Editor window edit the Computer Configuration by selecting the follwing items in order:
Computer Configuration
Windows Settings
Security Settings
Local Policies
Security Options
3. Disable the following User Access Control policys:
4. Close the Local Group Policy Editor window
5. Restart Windows
Notes: