i think its your graphics card, especially for games.
i think ram will only increase in speed if there are a lot of programs running.
i dont know how good your CPU is either.
EDIT- aww... beat me to it.. haha
EDIT- i saw the requirements of C&C Kane's wrath, not sure if its the game you are talking about, and it seems like my laptop is able to run it, so i guess the specs arent high.
Maybe you have some spyware/adware or any of those slowing your computer down, or only have about 1gb of free space left, or it just needs to be defragged
Desktop -Cooler Master NV690/AMD Phenom II X4 965 BE/MSI 880G-E45 Motherboard/2 x 2GB DDR3 G.Skill Ripjaws X/Sapphire HD 5870 1GB GDDR5/CORSAIR CMPSU-550VX/Seagate 7200.12 500GB (OS), Samsung F3 1TB (Storage)/Sony DVD Burner/Windows 7 Professional 64-bit