The date on my calender has changed to 25th November. How do I change the
date back to the correct today's date?
Try Control Panel > Date and Time.
If it keeps losing the date and time after it's been switched off then your
CMOS battery probably needs replacing.

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TechieBird
http://bwain-dump.blogspot.com
> The date on my calender has changed to 25th November. How do I change the
> date back to the correct today's date?