Currently Being ModeratedJan 6, 2013 2:43 AM (in response to foxbat-7395)
Welcome to the Apple Support Communities
To start into OS X, press X key while your Mac is starting, or press Option key while your Mac is starting and choose "Macintosh HD". If you want to start always into OS X, go to System Preferences > Startup Disk, and choose Macintosh HD.
If you want to delete Windows, open Boot Camp Assistant and follow the steps to uninstall Windows
Currently Being ModeratedJan 6, 2013 3:38 AM (in response to foxbat-7395)
Well I hate to be the bearer of bad news but your install of Mt Lion is also more then likely registered to the previous owner. Unless that used Mac is from 2012 and originally bought after June of 2012 it should not have Mt Lion installed on it.
Good Luck and Best Wishes
Currently Being ModeratedJan 6, 2013 2:30 PM (in response to foxbat-7395)
so very grateful to you both. the instructions to open mac worked a treat