As Pauln90 states, the PC will only work if it's specifically designed for dual-voltage. This is extremely unlikely.
While it's possible to buy transformer to drop the voltage from your wall socket down to that required by the PC, it would probably be simpler to replace the PSU (power supply unit) inside the PC. A local computer shop should be able to supply and fit a new PSU for no more than �50. (Don't go to PC World. Their fitting charges are ridiculously pricey. It would probably cost you nearer �100, with fitting, in one of their stores).
Chris