How do i know how many memory slots my computer has?

Google is a wonderful thing.

Memory

RAM Technology DDR2 SDRAM

Installed RAM What is "Installed RAM"?

1 GB

Max Supported RAM 2 GB

Number of Memory Slots 2 x 240 Pin DIMMs

Supported RAM Speeds 533 MHz

You could go to the Compaq web site and type in your model number - there you should see it listed as part of it's stats.

Generally "rule of thumb:" Most pcs today have at least 2 slots with which you can upgrade to a minimum of 1 GB.

As long as your pc is unplugged, you can crack it open and see your slots for yourself without dismantling all of your perpiherals. Pretty easy, actually.

Your machine has 2 memory slots and can handle up to a maximum of 2GB of memory. it uses DDR2 memory.. What is referred to as PC2-4200 240 pin DIMM. To get the maximum memory, you will have to install 2 1GB memory modules.

Go to http://www.crucial.com/ and use their memory configurator. it will tell you what you need.

The PCI slot has nothing to do with the memory. PCI slots are what add on cards plug into, like a network or sound card.

Honestly, it would probably be a good idea to ask your question at the HP forums (compaq is owned by HP): http://www.hp-forums.com./ It is a free service and will be able to answer a lot of your questions. You can also interact with a bunch of other users that can give you useful tips. Good luck!

Your computer has two 240-pin DDR DIMM sockets supporting PC 4200 (533 MHz) and PC2 5300 (667 MHz) DDR2 DIMMs (non-ECC memory only, unbuffered).

Your system has one PCI Express x16 slot and three PCI slots.

Google is your friend. :-)