yes, put the paste on the heatsink, attach cpu - you said this was an older computer - does the heatsink have a fan or not? I have worked with some that have no fans attached, but the process is similar, except there is no fan to go with the heatsink. Make sure you replace the cpu in the socket very carefully so as not to bend any of the pins.
If a known working power supply produces the same results as your power supply then you need to go through the procedure I outlined for you in my previous post. It is imperative that you eliminate the other parts of the system, however, if the heatsink and fan are visibly NOT contacting the CPU properly then you probably need to replace them.
Will the computer shutoff after 5 seconds of being on if there is nothing attach to the power supply.
No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.