Need to revert back to IE8 (from 10)

Howdy,
I work at a school and there's this computer that has Win8 with IE10. Some school websites require IE8 to function properly. So, I've googled it and tried a few techniques (recently installed programs, compatibility mode, developer tools/run as IE)... but to no avail. The latter (developer tools F12 and run in IE8 mode) might work, but it doesn't save that setting, meaning I would have to set it every time. So that solution is completely worthless.

please help
(windows 8 blows)