Question : Problem: cpu tester (not a stress / stability test)

Am looking for a good (free) bootable image/software that will test if a cpu is good or not... am not looking for a stress / burn-in / stability test i need something that will really test if it good or not.

Thanks

Answer : Problem: cpu tester (not a stress / stability test)

Its called a BIOS post.
What you ask for is not practical as a CPU is dependent on all other components on the motherboard to function as they are dependent on the CPU. The BIOS in the POST(Power  On Self Test) actually tests the CPU before any other component. Once the CPU has passed the test it carries on to test other components.
Stressing the CPU is the next best test as the heat that is generated by working through the computations will show if any hidden defects are present under temperature.