Have you ever experienced an electrical shock when opening a refrigerator? This happens when the refrigerator cabinet electric potential is different from zero. As you are contacting the floor, that is at ground potential, there will be a potential difference between yourself and the refrigerator, building up an electric current as soon you contact the refrigerator metallic casing, causing the electrical shock.
This same kind of problem may happen with your computer cabinet or with any electrical equipment having a metallic casing.
The ground wire function is to provide a zero volt reference. Ground wire is directly connected to the metallic casing of the equipment whereas you will never feel such kind of shock in properly grounded equipment.
Now you figure that you are connecting the PC to a printer. That connection is done by means of a cable, right? What happens if the computer casing electrical potential is different from the printer casing? At worst, you will blow the parallel port of your computer or the printer's.
Another frequent situation is found in networked computers. If the computers are not properly grounded, you'll burn their network card whenever their casing show different electrical potential than yours. The network cable will play the role of interconnecting the computer casings provoking a shock between them, just as you experienced a shock when contacting the fridge door or the computer cabinet. This shock is an electric potential difference that will cause at least the inoperativeness of the network and, at most, the burning of the computer network cards having a potential difference between them. That is what happens in networks having several computers (naturally this problem only happens in cabled networks conducting electricity, while in optical fiber networks this problem will not show up, as fibers transmit light, not electricity).
There may be a potential difference between equipments that are going to be interconnected. The solution to level this potential difference is grounding.
But, as we've discussed earlier, in many cities in the world there is no ground wire distribution and it may be expensive to do it, because as we've discussed, one must bury a steel/copper bar into the ground - if you live in a house that is quite a simple task, but if you are in the 10th floor of a building, that could impose quite some handwork).
Then, what is the solution to level the potential difference between equipments? Unless you're working in an office where there are several networked computers, where a real ground is required, one can always use the "virtual ground" technique.
In your stand alone computer you will not have this potential difference issue between computer and peripherals, once you just level their potential difference. To do that, just interconnect their ground wires. Your voltage stabilizer can do that for you. Just don't cut off the ground pin of your equipment mains plug, and connect them to the same stabilizer in order to have their potential leveled, as the stabilizer interconnects all ground wires of its outlets. The only problem happens if there is a potential difference between yourself and the cabinet case, as you may experience an electrical shock whenever you contact any metallic part of the cabinet, or if you network several computers. Then ground will really be need.
If you want a true ground, however, we suggest you look for the assistance of a qualified technician specialized in buildings installations.