Yosemite won't accept administrator password I've just bought an iMac, reinstalled Yosemite, put in my details but, coming back after a short pause, found it had gone to sleep and wouldn't accept my password to wake up. I'm sure I put in the right one. I've seen advice that re-booting to Recovery might offer a way of recapturing my password, or changing it to a new one, and tried it again and again. But whether I restart holding down Command+R, or holding down the Option key and then choosing to boot from Recovery, I just can't find any options to click that would lead me to either my password or any way to put in a new one. 

I'd be grateful for help.
Once you are in the Recovery Mode, click in the menu on Utilities, then Terminal.
Type resetpassword then enter.
Follow the instructions on screen


Warning: Your keychain can only be unlocked with the old password.