This is so you can't identify the pest. Did you try Grif's advice? But first YOU may not want to touch that friend's laptop. It's not yours and who knows if the pest is a bomb. That is, your friend may be very upset that the machine won't boot after removing the malware/virus/trojan/whatisit?

Here's Grif's advice on how to scan it. After you find what it is, then back to the web for what it may do.