ya you could easily put in 2 more sticks of ram,the only question is which one,check your documentation to see which ram its running with(ddr,dd2)and at what speed or if you dont know then post back either your hp model or the mobo name and we would be able to help you out with that.also if you do know which ram then it wil be a good idea to put in the ram fromthe same manufacturer that you have already got,its not a big thing if you put in any other brand ram but you wouldnt run into any incompatibility,speed or after sales support later.