Dual channeling is supported by some RAM chips when you have two in at one go (for example liek you have, 2x 512 chips). It also has to be supported on the motherboard as well.
Basically what it does is gives the RAM double the bandwidth for data, making transfers faster, and so giving more performance!
SOME IDEAS TO GET BIOS:
Have you tried pressing Del then? and its just come up with some HP settings? Instead then, check when it is booting up. Does it say a button to press instead to go into bios? Check carefully, as it might have been changed for your HP computer, but it will be there, don't worry, and will then allow you to change settings and check for the above.
If you need more time to look at the menus at bootup if there going to fast to see and so you might not see the bios button to press, try and press Pause/Break on the computer keyboard, which was used in the olden days of computing for some tasks, and nowadays it can be used to slow down menus like this that might go past too fast, so try pressing that
As soon as you find the button, restart and keep pressing it until the Bios menu appears. You can then start looking
i hope this helps