My laptop was infected!
It happened when I loaded PSP games from a known game loading station. I loaded 2 games. After some days, I tried to load some games from my own netbook. When I plugged it into the USB port, my anti-virus program detected trojans in ALL of my PSP's folders. My netbook didn't shut down so I just pressed the off button. The next day when I tried to turn it on, it wouldn't! We brought the laptop to the NEO laptop center for check-up. It was reformatted. We just got it back today because it was brought
to the main branch.
So if you load games from your own computer, NEVER load from game stations.