PC keeps shutting down for no reason

[wayne100]

my acer aspire keeps shutting down especially when i am using convert x to dvd,also it seem to be over heating and i dont see any fans (desktop)

 

[Novuake]

Download this and install this :
http://www.cpuid.com/softwares/hwmonitor.html
Download link is on the right.
Run it in the background and report max temperature to us.

If it is overheating, which it seems to be. You will need to open the case while running. Check is the CPU heatsink is clean and if all fans are running.