I used to just turn off the blocks. First by going into regedit, but they blocked access, so I made a .reg file at home and then ran that which changed the registry without having to open regedit. Then they blocked .reg files, but I found out you can run a .reg file though command prompt, but command prompt was already blocked, but the way it was blocked was so that it automatically closed when opened, so I made a flash file that automatically refreshed itself over and over, ran I loads of times so it lagged the computer to fuck, then imported the .reg file with command prompt before it had time to close.
Then they changed how they blocked it, and instead of disabling the ways to unblock it, they had a .VBS file that ran on a loop that kept turning them back on while you were on the PC. I found the .VBS on the system, changed the 1 to a 0 in the string that turned on the blocks, and ran it again, so instead of turning them on constantly, it turned them off.
And then I left school. According to my brother who's still there, using the .VBS still works, but they've started banning anyone's account they catch with it.