My computer shut down by itself

My computer shut down by itself

My computer is 7 years old (with small changes). It shut down by itself
and I think there is a problem with the temperature.
CPU Type: DualCore Intel Pentium D 945, 3416 MHz (17 x 201)
Motherboard Name: Gigabyte GA-8I945PLGE-RH (3 PCI, 2 PCI-E x1, 1 PCI-E
x16, 2 DDR2 DIMM, Audio, Gigabit LAN)
Video Adapter: Radeon X300/X550/X1050 Series Secondary (512 MB)
From the beginning the temperature was high and when I started a program
raises at 92-95. I don't know a lot about computers.
Any suggestion would be helpful.
(Sorry for my English)