I have an HP lap top DV8T with 8GB of RAM installed. The BIOS & System show 8GB installed but only 4GB usable. I am running Windows 7 Pro, 64 bit version. I've tried switching the memory stricks around with no success. Need help
Look in your manual, under what is available in bios.
Laptops have very limited User changable bios options.
I looked on HP web site and did not see.
What I would do is view your Bios and look for antything that is connected to memory.
.. If nothing found, EXIT without saving.
I have a feeling you have either a defective Module, or one is not fully seated.
Remove both sticks.
Install one stick in primary memory slot.
Power on and check, should boot to windows and show 4 gigs installed.
.. Note you can down load Prime 95 and test this first stick. Or download an iso for Memtest86, create a bootable memtest CD. Insert CD and boot to CD, run at least for 1 -> 2 hours. - Checks A OK, then
.. Remove this stick and stick in 2nd module and repeat above.
Both sticks check OK, then
re-install both sticks, and repeat test.
.... You could try remove and re-inset memory modules and test, if that fixes, then problem was connection, IF NOT then do the single module check.