i am getting the message "out of memory" on such and such line, while i am using internet explorer?

First one of your problems could be. memory speed the 2 512 sticks will not be as fast as the 2 1 gig. What happens is the system will default to the slowest memory hence your 2 1 gig sticks will run at the 512 speed, so whip them out as they will be doing your system no good. next update you xp to service pack 3 that's been out months now, IE is the worst web browser out download and install firefox web browser it is more secure and faster,

Next windows is a memory hog and it's a second rate operating system to start with, you being a windows user wouldn't know the difference any way, because that's all you have used, I will give you some advice it's up to you if you except this advice, You have a 64 bit system running a 32 bit operating system (what a wast of processing power)

To get the best out of your system you need the best, Fastest and most powerful operating system there is (windows is not it) You need to be looking at the latest 2010 Linux operating systems of which there are many 64 bit versions available, free to download and use with all the application software you will ever need, By the way HP support and install Linux, If you live in the states you won't know this, You can't buy a Linux system there.

If your into games then I suggest you have a look at Sabayon Linux gaming they have just released their 2010 version, today 24/12/2009 the download is 3.6 gigabytes which is full of Linux games these include 3D action games, and you can play windows games on Linux

here is the website link

http://www.sabayon.org/download

windows help, type in system info, options there, will tell you how ram is active. also should say how much is being used in task manager.