comuter reboots after loading

[Jealsj]

hi
For sometime now I am unable to work with one of our computers. It keeps reloading once it reaches the desktop. I tried reinstalling the operating system but it won't boot from the CD even though the cd rom is the first boot choice.
can anyone help?
Thanks a lot

 

[crjdriver]

It would help if you posted the exact specs of the system you are trying to fix.