A-Tech 4GB KIT 2 x 2GB HP-Compaq Presario Notebook C756CA C757CA C764NR C768CA C769US C770ED C770ES C770US C777NR C780ES C790EC C790EE C790EI C790EP SO-DIMM DDR2 NON-ECC PC2-5300 667MHz RAM Memory 4GB KIT (2 x 2GB) SO-DIMM DDR2 NON-ECC PC2-5300 667MHz RAM Memory Genuine A-Tech Memory Lifetime Warranty Toll Free Technical Support 1-866-557-4527 Designed For HP-Compaq Presario Notebook Series. (See Compatibility List Below)