The powers to be in Government in Australia decided last year to make changes to the starting and ending times for Daylight Savings In Australia. As a result, the end of daylight savings has been extended to the first Sunday in April. Some PCs which have not been patched may automatically switch off to non DST time. This problem particularly affects Windows Mobile devices.
To resolve this issue on PCs and Servers, you will need to apply the Microsoft August or December 2008 Cumulative time zone update. If either patch is applied, the PC will have the correct DST information. This patch can be downloaded here – http://support.microsoft.com/kb/955839/
For Windows Mobile Devices, you can download the patch here using IE from the device- http://mobile.microsoft.com/en-us/windowsmobile/updates/dst.aspx
The patch does not require a reboot.