|Look at the label on the power supply carefuly and see of it has something like 110-240v AC 50-60Hz, that is if it is in English, which most are. If there is such a label then you have no need to switch voltages. Every power supply I have seen has had either s switch to switch voltages or it has been auto switching.|
A lot of power supplies have auto switching for voltages and will automatically adjust to the input voltage. I would suspect that one made in China would have this facility as they will be exporting all over the world It would not make sense for them to restrict their market to a single area when for a few dollars they could make it universal for the world market
One thing to remember if you are in a 110v area and the power supply is designed for 240v and you plug it in, it wont do any harm, it just wont work. It is the other way round, 240v into 110v that the sparks begin to fly.
If you do really do have to buy a new power supply it is the mains voltage of the country you are in that is the deciding factors. The computer it is being used on is largely irrelevant as the power supply will take cars of its power requirement providing you get one that is of sufficient power to do the job.. You may still have to buy a new power lead to fit the power sockets where you are.