When I load my PC the time is always out 1 hour. Right now it's showing 1800 when it's 1700.

Set time automatically is On.

Time Zone which is disabled is (UTC+12:00) Auckland, Wellington

When I click 'Sync now' it corrects itself and stays corrected until i start it up again. It's effecting a few websites so it's a right pain.

Genuine Window copy. 

Any ideas? Google says to set time automatically to on etc which it's all showing correctly.