System Hangs

[Jesse Brent Coats]

My system freezes and neither Ctl-Alt_Backspace, nor Ctl_Alt_Printscreen
<various keys> doesn't respond.  Windows doesn't seem to suffer the same
trouble.  On boot, I can enter a utility that displays motherboard and
cpu temps.  What are acceptable temps for these components.  (someone
had suggested that my system may have been overheated.)
I love Linux, but system freezes are unacceptable.