The Sony Vaio PCG-C1MHP is an ultra-portable laptop. However, as it is a bit dated now, you may want to perform upgrades such as increasing RAM or possibly replace a harddrive. CAUTION : Doing this will invalidate any warranty you have with Sony.

The first step is to remove all peripherals attached and any power. That includes the battery. Place the Vaio on it's lid and unscrew the screw nearest the RAM compartment (indicated in the image below).

Then place the latop on it's base and remove the keyboard. To do this, locate small tabs at the base of the keyboard (in the bottom left and bottom right corners below the Ctrl keys).With a small flathead screwdriver, gently prise the keyboard tray from the base, starting on the left hand side. Do not pull the keyboard up forcibly as you may snap the ribbon. Rather, once you have the left hand side raised, do the same with the right hand side, then gently lift the tray to the side. You will then see the harddrive which can be removed by vertically lifting the end of the cable from the motherboard (circled in the image below) and removing the 3 screws as indicated below.

Once the Harddrive is detached, you can unscrew it from it's holder.

The Vaio comes with an IBM Travelstar. This brand is now under the Hitachi umbrella.A good replacement is:

Hitachi TravelStar 5K80 - hard drive - 80 GB - ATA-100
Form Factor 2.5" x 1/8H
Dimensions (WxDxH) 7 cm x 10 cm x 9.5 mm
Weight 0.1 kg
Type Hard drive - internal
Data Transfer Rate 100 MBps
Interface Type ATA-100
Buffer Size 8 MB
Capacity 80 GB
Average Seek Time 12 ms
Spindle Speed 5400 rpm