Apple Mini mid-2010 refuse to reboot after IOS update

I have an Apple Mini mid-2010, originally with IOS SnowLeopad 10.6x.

After upgrading to Yosemite, reformatting the hard drive, trying to restart the computer, using commando r (reboot), deleting and formatting the the hard drive, it refuses to reboot and then I am trying to reinstall from the original CD with SnowLeopard 10.6.x it refuses to boot from that one, but just show the apple bar, the start of the progress bar, and stops there and get really really hot ... What's wrong and what can I do in order to try to solve it?