1) Try using our memory alone in your system then you can add your previous memory.
2) Install the largest capacity module first If system can use singe memory stick then install 1 at a time.
3) Make sure the memory is seated in properly most problems are solved if you install right. Specially Laptop notebook has this problem memory is not installed correctly.
4) Update the BIOS to the latest version before you install the memory.
HOW TO UPGRADE BIOS ?
Please visit your machine manufacturer website and download latest bios for your machine. Here are some popular Computer manufacturer sites.
