If after an unsuccessful install attempt of a new memory upgrade your old memory is also no longer functioning, a likely cause of both issues is one of the following factors.
Improper Installation: Double-check your install steps (Desktop,Laptop), paying special attention to ensure you are using enough force to seat your parts and using the appropriate slots for installation, to be certain the modules aren't simply incorrectly installed.
Power: Be sure you've firmly reconnected power cables disconnected from your system when you began, both at the outlet and into the computer itself.
Loose Internal Cables: Sometimes the force used when seating memory can flex your motherboard in such a way as to loosen your system's internal cables. Be sure all internal cables, especially between your internal power supply unit and motherboard, are still firmly connected.
BIOS Conflict: Sometimes it is necessary to clear BIOS settings to solve boot related issues. Your BIOS/UEFI may have a soft reset available for this process, or a jumper which can be used in place of the below steps but to otherwise manually clear the BIOS/CMOS install the memory and follow the instructions below:
1) Turn off the system and unplug it. 2) Remove case cover/panels. 3) Once the system is open touch an exposed/bare metal part of the computer to ground yourself. 4) Looking at the motherboard you should see a small silver circular battery (Like a watch battery). The battery will be held in place by a plastic holder. 5) Remove the battery from the motherboard. This is usually done by gently pressing the metal clip on the plastic holder. The battery should pop up/out on its own. 6) Once the battery has been removed please leave the computer sitting like that for around 15 minutes. 7) After 15 minutes replace the battery and the cover/panels 8) Reconnect all cables and power up the computer.
If the steps above don't help, please contact us for further support.