i was going to make a home theater PC to hook up to my 50 inch living room TV. i wanted to make it as cheap as possible because i was just going to use it for you tube, hulu and netflix. but then i found HP dc7800 i am going to put the cheapest video card i can find that has HDMI and hook it right to the TV. the HP dc7800 has 2GB DDR2 ram. i was wondering if i had to buy DDR 2 ram or can i get DDR3 ram. and if i can use DDR3 ram do i have to remove the DDR2 and only have DDR3 or can i mix it. and any suggestions on the best brand or types or best deals will be taken in to consideration i have no idea whats a good brand or price for ram. thank you for all ur help and support for this and every other tec query i posted in the past.