Need help with Computer

Ok, Ive never had any luck upgrading the RAM on an HP, was wondering if anyone can help me make sure I get the right stuff.

My computer is a crappy HP Pavilion a230n(PDF Spec Sheet) (http://www.hp.com/hpinfo/newsroom/press_kits/2003/desktops/ds_paviliona230n.pdf)

I believe the ram in it is PC3200, but Ive tried just using that before and it never works. I'm planning on getting a 1gb upgrade from www.newegg.com, but don't want to order the wrong one.

Any help is appreciated.

You can get any of the ram on this page
http://www.newegg.com/Product/ProductList.asp?Category=17&N=2010170147+1052107965+1052407860&Submit=ENE&SubCategory=147


It looks like your computer comes stock with PC2700, so i'd suggest getting that