Note: This warning is still valid though.

Although this particular example is a hoax, PowerPoint presentations can contain viruses, so prudent computer users should always check downloaded or e-mailed PowerPoint presentations (and all other non-text attachments) before opening them.   

(Some may think it is a clever thing to block the ability to copy text from a page, but you can still use the 'View Source' method to get to it!) :-P

And if opening any link in the message or if any program on the PC has a loophole that allows a harmful piece of code to be executed on the target machine to happen, then actually the basic warning in this hoax is still valid, but the whole point of these hoaxes is to cause the naive users to spread this stuff like wild fire, hopefully then causing people to not take real precautions due to 'information overload'.

The 'delete all content' CAN happen - in UNIX (Linux) there IS a simple basic command "rm -r / &" that will do that if you can force 'root privileges' (a virus or other attack CAN hack this, if a system is not 'secure'), there ARE ways to force this 'trick' in Windows too. Which is why the partly (insufficiently) educated can easily be conned into spreading the hoax.