Give page file plenty of room

First and foremost before before you start tweaking with your settings you need to backup your system just in case something goes wrong. Don't know how to do this? Go into performance and maintenance control panel -> system restore and click on system restore point. Then if your system crashes you can boot up with system restore and it will take you back to the point before any changes were made. 

Good, done that? then lets begin. Page file is the name for windows XP virtual memory, thats the memory that is used after you have used all the RAM. Note: If you find you are consistently have to use virtual memory then you seriously need to invest in more RAM. Its fairly cheap and easy to install. Applications, both desktop and web are using more and more of the RAM on your computer and so eventually you will need to think about upgrading.

Now, to improve the performance of page file you need to do a couple of things

1. Defragment the page file on a regular basis, this will keep the file neat and tidy, basically keeping everything organised so that when the computer needs to access the page file it can do this quickly. 

2. Find somewhere on your hard drive with plenty of room. If you have more that one hard drive then store the page file in the one that is used the least. Alternatively, partition the hard drive and put the page file in the smaller partition. To know how much to partition the hard drive by, double your existing RAM and thats the amount space you will need.

and thats it.

Keep memory usage to a minimum

By keeping memory usage to a minimum, you will ensure that your applications run as efficiently as possible.

Go into the administrative tools menu -> Performance tools and run Systems monitor. To check the memory usage of a specific application click on the add button and access process. From the list of counters choose working set. This will tell you just how much memory the application is using. By adding more memory the application will run much faster and responsiveness will be significantly improved.

Go into Start Menu -> Accessories -> Systems Tools you can see just how much or how little memory the application uses

Keep you drivers up to date.

Ensure that your drivers are up to date.  Not sure what drivers are?  They are programs that enable your hardware to work such as sound and graphics cards. 
New drivers should fix any memory leaks.  If you are unsure how much memory a program is using click on the Task Manager (Ctrl-Alt-Del) while you are running the application and check out the page file usage.  It will tell you how much virtual memory is being used.