The server time label displays the actual time on the server. If you only use VisualCron locally you will not see any difference from your local time. The server time is used by VisualCron for running of Jobs.

The displayed server time is only updated when you log on to the client. If you change the time on the server, it won't be shown in the client until next login. However, this does not affect the running of Jobs.

The format on the server time is based on your regional settings. If you want to change the format you go to Windows Control Panel -> Regional Settings. Changes won't take effect until you restart VisualCron.