I would not do this. Wait till after HP fixes the machine.
My laptop, a dv9000 series, qualifies for a warranty enhancement as described here:
I can't send in my laptop right now until I have a replacement arranged for me to use while mine is being fixed.
In the meantime, if I replace the 1GB that came with my laptop with 2GB will that affect my warranty at all(have to open the machine to install it etc.)?