Dell Inspiron 15 3542   Win 7, 64bit  shipped w/ 4Gb mem single slot.  Replaced with an 8Gb of same speed, voltage and timing.  Bios sees 8Gb.  Windows sees 8Gb but reports 3.41Gb usable the balance in "Hardware Reserverd" state.   No options in Bios to reserve memory.....Stumped.  Any ideas?

Also ran the Dell diag, no issues.

Thanks