Double-click the clock in the systray... (?)
To choose a different calendar Open Regional and Language Options in Control Panel.
On the Regional Options tab, under Standards and formats, click Customize.
On the Date tab, in the Calendar type list, click a calendar type.
Notes
To open Regional and Language Options, click Start, click Control Panel, and then double-click Regional and Language Options.
If Calendar type is not available, your location does not support multiple calendars. The region selected under Standards and formats on the Regional Options tab determines whether multiple calendars are available.
