Reset password. Is it work on OS X 10.8? If I haven't boot disk or recovery?
1. Turn on macbook and hold Command and S
2. Type: mount -uw /
Enter
3. Type: launchctl load /System/Library/LaunchDaemons/com.apple.opendirectoryd.plist
Enter
4. Type: ls /Users
Enter
See users list and choose yuor user
5. Type: dscl . passwd /Users/username password
Enter
username is your user username, password is your new password Can I use "emphty" password (no password)?
If you come out notice "not finding a file / directory" - just ignore it.
6. Type: reboot
Enter
All above is for OS X 10.7
MacBook Pro with Retina display, Mac OS X (10.7.4), MAC OS X (10.8) - not found in list