Backup your F*#king files now!

Something dramatic happened just a while ago.
Was trying to uninstall that QVOD player, which is the program needed to watch videos from tom365.com, as it was all over my main folder. As i was lazy during the installation, i did not assign a specific folder for that particular program, so i saved it in my main folder. As it was installed, the sub-files were created in the main folder and that made my folder look very messy, and attempts to cut and paste them to a separate folder made the program faulty. Hence i thought of uninstalling it, and installing it in a separate folder the next time.
Then, IT HAPPENED
As it was unstalling, it started to delete the rest of my files that were in the folder. All my photos, videos and semester 2 sch stuff, all gone. Basically the whole folder was empty.
Tried to reload the backup, but i realise i had NO shadow files saved, as i did not back up using the com's backup function. Luckily i did manually saved my files in an external HD at the end of last year. So stuff for the new sem and recent photos/ videos were the victims for this time.
I'm really sad as all the precious videos I took during a recent Genting trip with gal were all gone, along with the photos taken. Gone too were the saved copies of the V-day card design, CNY photos etc.
I guess it's a good lesson, but at the same time, a really hard pill to swallow.
How wish time can be reversed, to undo my stupidity.