Can someone please explain to me what does this mean as i would like to purchase a netbook but it has this in its specs "UMA-No External Video memory" does it mean i cant play games on it or watch videos?
I don't think the UMA is part of it as it relates to wireless/mobile stuff but No External Video memory basically means no dedicated video memory and it uses the normal system ram in a shared configuration like many Intel gfx chipsets do.
Upper Memory Area - No External Video Memory. Uses your conventional RAM instead of the RAM of say, a video card, as ponder pointed out. Video is quite possible, but I wouldn't try playing Crysis on it.
It will play videos up to DVD quality just fine so that covers youtube clips as well. It will play 720p content OKish but anything above that like full HD is a no go.