This was back in class 10th...Our CS teacher once quipped in the practical Lab: If you reprogram the time in the CPU, and set it a month backwards, your HD will have all the data you had back then, even the content you have deleted!!!
I actually burst out laughing. He told me to get out. I happily did
It's better to stand in the corridor than to listen to a guy confused between time and System Restore.
Worst Comp teacher ever. He knew one thing about computers, and that was how to hide files and set passwords on zip files. He would drag about the same all day...and every 5 mins, he would snap out his new HTC phone to 'check the time'. Smartphones were still rather expensive those days...it was actually stolen 2 months later