If I were you, I would install the old kit, then adjust the BIOS settings to be manual. This let's you raise the voltage up a little, like from 1.8 to 2.1 (check specs on your RAM). You might want to specify the manual timings for the RAM (5-5-5-15).
Once you've adjusted the voltage and timings to be manual, reboot, see if the old ram by itself boots at this setting. If it does, try adding the new ram.
If it still doesn't work, try adjusting the timings to slightly lower, like 5-5-5-18, 5-5-5-25, or 6-6-6-25.
If you are overclocking, that changes alot, please tell me if you are.