Why does my new iMac keep freezing for no apparent reason?

Why does my new iMac keep freezing? This usually happens when it is not being used and is particularly frustrating when I do need to use it and ahve to switch off and then on again and wait for it to reboot.
I am not computer literate so keep any answers as simple and idiot friendly as possible. I treat it like a car. If I put in the key and turn the ignition on and the enginesprings into life I am content. If not.............. well!


In order to provide any help we need to understand a little bit more about the problem you are experiencing.
You indicated the issue occurs when the sytem is not being used. Does this mean that you stop working on the system and the system 'goes to sleep' where the screen goes black, but when you need to wake it back up by pressing keys on the keyboard or clicking the mouse the system doesn't wake back up? To test for this issue open the System Preferences and click on the Energy Saver preferences. See the 'Computer Sleep' slider to the far right 'Never' setting. You can set the 'Display sleep' setting to any number you prefer. With these settings see if the issue still occurs and let us know the results. If it resolves the issue then give Apple a call and let them know you are unable to wake the system when it goes to sleep. You shouldn't be having that issue.