yesterday I installed OS 1.1 on my nspire cas with touchpad, then I found the keyboard worked wrong. so i update to os 2.1
but! i made a mistake and I installed os 1.7. than i found i can't open my nspire cas! it just has black screen and reboot.
and i can't use ctrl+home+p+on to delete the os [on touchpad, home is on]
what can i do?
sorry for my bad English.