Any 2.5" SATA drive should work. There should be no problem using a 7200 rpm HDD, 5400 rpm HDD's are used because they are less expensive and they also draw less power so the battery lasts longer. I might suggest an SSD though if you can budget it, it uses even less power and the speed is impressive IMO.
Hope it helps
thanks, well it's just to make it work, i was thinking ssd as well. but paying lets say around 100$~115$ for a decent drive and sticking it in a 4year old comp doesnt make sense to me
. I was reading the WD scorpio black, "supposedly" it draws same power as 5400RPM so will be good, 7200rpm will be an upgrade enough