Sony make some nice hardware but they tend to do annoying things with it. Such is the case with the VGN-TX2XP and the fact that to get to the hard drive you have to disassemble the case. It's not too hard (once you know how) but I wish they'd do the same as other laptop manufacturers where only one or two screws need to be removed for access.
1. Remove the battery and undo the seven case screws on the underside. More screws are visible but only these seven screws (which themselves are arrowed on the case) need be removed.
2. Using a small flat-blade screwdriver, push down the spring loaded tabs (arrowed red) which hold the keyboard in place and gently start prising up the keyboard. It will be necessary to lever the keyboard over the non-spring loaded tabs (arrowed green) but if done gently (without twisting) it shouldn't be a problem.
3. Unclip the keyboard ribbon cable to remove the keyboard.
4. Unclip the ribbon cable towards the top of the unit (below the speaker grille) that connects the front panel buttons to the motherboard.
5. Undo the case screw above the trackpad.
6. Starting from the rear, unclip the upper (silver) half of the case from around the hinges and work your way around until the upper case is separated.
7. To remove the Toshiba 1.8" hard drive, undo the three arrowed screws and remove the metal surround. Above the hard drive is the Intel 2200BG wireless card and to the right is the DVD writer.
Reassembly is the reversal of disassembly.