Is it possible to replace my hp 6910p HDD with another 2.5" one, its a 80gb, 5400, 1.5 sata and i noticed a 250gb, 5400, 3.0 sata for £20 second hand and dont want to waste money trying it to find out it does not work , another quick question would i better off buying a external HDD is there any advantages to internal like there is with phones where you officially need internal for apps, games etc. thanks in advance