Hi Aykut,sorry i ave seached every where and i can not find any info,i guess asus does not want to let anyone upgrade,personally i have now given up,i ordered a dell 27 inch xps one i7 from the dell outlet online store,i know you can get into the dell,so i guess asus has lost another customer,shame really as i did like the asus et2300,you may get some info soon as the et2300 has been out for a year now in the uk and the warranties will be expiring,so i think some brave person will have a go at getting it open,i did find a hidden screw on the back,under a very small black plastic cover,but when i removed it the back cover only lifted slightly,i have tried removing the rubber feet from the base but no screws,i think the hard drive is located behind the screen,once or twice i felt a slight vibration and when i move the screen slightly,it goes away,i have also tried using a credit type card round the edge of the metal top plate on the base,but no luck and i did not want to force it,i have a feeling that the metal base cover is on with consealed clips where you would need to know where they were to put the pressure on it,anyway,good luck and if i do find out anything i will post it,thanks Raymond.