Memory question

I have HP a400n computer with 2.7ghz processor in the beggining computer had only 256mb but a year ago I upgraded to 768MB right now I am thinking going 2gb total will my system handle it ? Will I notice I huge improvement?
I am running windows xp

 

You may need to check the motherboard, and number Of slots, as HP give this spec for your board, showing maximumum of 2 x 512 mb of ram, with 2 slots- if you click on the motherboard (M S I), IT WILL SAY 4 SLOTS, WITH MAXIMUM OF 2 GB, WITH 4 X 512.
mEMORY UPGRADES CAN MAKE A DIFFERENCE, DEPENDING ON WHAT YOU USE YOUR COMPUTER FOR.
http://h10025.www1.hp.com/ewfrf/wc/...us&lc=en&dlc=en&product=391284&dlc=en&lang=en
.............If this is your motherboard (4 slots)
http://h10025.www1.hp.com/ewfrf/wc/...91284&lang=en&docname=c00058048#c00058048_doc

 

according to pny's site, you can upgade to 2 gbyte.

http://www2.pny.com/configurator/index.aspx

and, yes you should notice an increase in speed. g/l