They also bios lock PC's so that if stolen it's harder to access the bios system to allow you to change the boot up sequence.. you can't re-format a stolen pc and load up a new operating system very easily if it will only boot from the C drive and the accounts on that are password locked
Believe me, if your mate buys a cheap laptop from someone who is not quite legit then it can take a bit of effort to get the laptop running again
