Latitude E6510 - 8GB RAM upgrade troubles

Hello,

I have a Dell Latitude E6510 (Intel Core i5 520M, 2GB PC3-10700 RAM, Intel HD Graphics, Dell A07 BIOS, Windows 7 Pro 64-bit).

My company recently purchased me 8GB of RAM (2x 4GB PC3-10700 modules), however a weird situation is occuring:

I can boot Windows 7 Pro 64-bit with either of the new 4GB modules individually (4GB at a time).

I can boot Windows 7 Pro 64-bit with either of the new 4GB modules in combination with the original 2GB module (6GB total).

I can NOT boot Windows 7 Pro 64 bit with both of the new 4GB modules together (8GB total). With this combination of modules the BIOS recognizes the modules, starts the boot loader, and starts to boot Windows 7 Pro 64-bit... however it enters "system repair" mode, runs a quick diagnostic check, and finds NO errors.

I am hoping someone can shed some light on this perplexing situation.

Thanks,

Ron