I didn't catch what type of cpu chip we are dealing with..perhaps an Intel P4??? If so there is a small lever on the side of the boards pin array. It should be open when you insert the chip and then gently close the lever and cause it to be "latched" by hooking it under a very small indentation. A worry I have is if you had a hard time pulling the heatshield and hence the cpu chip from the MB as one the lever that holds the chip in place was already latched. Did you open it to insert the new chip????
If we are talking about a none P4 chip than my discussion is for naught.