Would you like to remove or upgrade memory on a HP Pavilion zv6000 series laptops? BIXNET.com published a great tutorial for a HP Pavilion zv6000 laptop, also should work for a Compaq Presario R4000 series laptop. Using this tutorial you’ll be able to remove, replace or upgrade laptop memory in a few easy steps.
This laptop has two memory expansion slots. One of them can be easily accessed from the bottom of the laptop. All you have to do is remove the memory door.
On the other hand, accessing the second memory expansion slot will take some time because it’s located under the keyboard. You’ll have to remove the keyboard in order to access the second memory slot. The tutorial has instructions for disconnecting the keyboard from the motherboard but it’s not necessary to disconnect the keyboard when you are upgrading the memory. Just turn the keyboard upside down and place it on the palm rest wile it’s still connected to the motherboard and you’ll see the second memory slot.
HP Pavilion zv6000 series laptop memory can be expanded to 2.0GB, up to 1GB in each memory slot. You should use DDR PC2700(333MHz) memory modules.

One guy asked me this question. Can I install memory with different sizes? Yes, you can. If you install 512MB memory module in the first slot and 256MB module in the second slot the laptop will see 768MB. Just make sure both memory modules run at the same speed, so both modules should be DDR PC2700(333MHz).

By the way, memory installation instructions for a HP Pavilion zv5000 laptops are similar.