Windows XP. But that is not the main problem about the computers in my school
The problem is: they are so slow, that you can...
Start the computer
Login
Go up 3 stairs, open your locker, grab some books.
Go down 3 stairs then go to the bathroom
Go back to the computer
Sit down at the computer
SMS your girlfriend, or your friends, or just play some games for 2-3 min
ALL BEFORE THE PIECE OF •••• HAS LOGGED IN SO YOU CAN START INTERNET EXPLORER 7 WHICH IS ALSO SLOW LIKE AAAAAH