I have a couple of options for you that should help solve your problem.
 
1) Head to www.4allmemory.com and run the simple (and safe) scan which will determine exactly what speeds of ram will be compatible with your system. (Do not purchase from this site, for it is fairly high priced generally. Shopping at tigerdirect.com or newegg.com has always worked well for me.)
 
2) Turn off your PC. Remove the power cord from the back and open your case. Simply look at your stick of ram and there should be a sticker on the stick itself showing the speed (PC3200/ DDR 333) or whatever it is. It will also show the stock CAS Latency and other info that is not important to finding a compatible stick.
 
Good luck! and I hope it helps.
 
PS) I noticed today that www.tigerdirect.com has sticks of Ultra 512MB PC3200 RAM on sale today for 30 bucks after a rebate. Very good deal on what has proven to me to be a great stick of ram if you aren't overclocking.

Well one option is to find your current memory stick ( if thats what your wanting ) is to go to bios, to do that shutdown your pc and turn it back on then the key they tell you see when it says your system name which is one of the following (f2 f12 or delte) once there you should see you system's memory thats one way or you could go to start run type in msinfo32 then hardware resources memory and that should show lots of things but assuming that you haven't upgraded to anything you should see something that says intell or some other name storage device if you cant locate it then on the bottom search for "memory" without quotations, if you're seeing whats compatible with your computer just go to kingston.com if you want kingston memory which i would recommend then type in your system model and boom.

thank you for suggestions