The Jewelry Shopkeeper doesn't have any control over your computer's date
and time. Your computer has an internal clock and calendar which the
Shopkeeper just reads.
To fix it, open the Windows Control Panel and choose "Date & Time"
or double-click the time on the bottom right corner of the Windows screen
Be careful to set the year correctly as the form by be unclear. Normally
the day of the month is selected from the calendar and the year is next
to the month. i.e. Don't choose October 31 where it's expecting
October 2005 (as 31 could become 2031)
You can also open an MS-DOS Command Prompt and type the word DATE and press
Enter and after fixing the date, then type TIME and press Enter.
To get to the Command Prompt run the JS-MENU icon
or choose Start, Run, COMMAND, OK.
Be careful to set the time correctly - e.g. make sure you don't set it
12 hours wrong.