need to know SPECIFICALLY which model this is..
example.. at hp.com looking up the "Presario 900" gives 20 desktop models, and just as many laptops.
the laptop models have at least 4 in just the 900 model line, not to mention 9xx series
as example:
? Compaq Presario 900AP Notebook PC
? Compaq Presario 900CA Notebook PC
? Compaq Presario 900LA Notebook PC
? Compaq Presario 900US Notebook PC
? Compaq Presario 908EA Notebook PC
? Compaq Presario 909EA Notebook PC
? Compaq Presario 910AP Notebook PC
? Compaq Presario 910EA Notebook PC
I looked at the 900US and it doesn't show under keyboard placement ... it shows access from underneath ... most laptops do have memory access from underneath, old old laptops sometimes had under keyboard type placement..
so.. specific model number please...
alternatively.. go to HP.com select "Support & Troubleshooting" near the lower left side, then enter your model number in the space provided and look for a Hardware Manual.