In order for a computerand today's day was yesterday, you need for a day to "rewind" it to the system time. This can be done from the BIOS settings the next time you boot the computer, from the operating system itself. The second method is much easier, so try to start changing the system time from it. In Windows, click with the left mouse button on the digital clock in the lower right corner of the screen in the notification area of the taskbar. This action is in the latest versions - Windows 7 and Vista opens a window with an analog clock and calendar.
Click "Change date and time" - it is placed under the calendar and clock and designed to access the desired settings of the system clock.
On the tab "date and time" (it opens by default) to look for a button will not have long - it says "Change date and time". Click this button and open another window in which duplicate calendar and clock, but this time their testimony can be changed.
In the calendar, click on yesterday's date, and it is possible to complete the operation. If you need to change the time, do it in the box under the analog clock. Then click OK in this window and the next.
In earlier versions of Windows, the steps are a little different. In Windows XP, double-click the digital clock in the system tray and right after that, you can begin to change date and time - these options open without additional intermediate Windows.
There is another way to open the component settings date and time, which is equally applicable to different versions of Windows. It is in the "manual" invocation of the target component in the OS file name. Press the key combination Win + R, enter a name for the file timedate.cpl and click the OK button.