Is this the same computer that died when you plugged it into 110v instead of 220v? If so, I'm with ottens flavor and I'd also be checking the memory modules.
nope, the one you mentioned was pentium 4 of 512mb ram which the power supply died.
this one now is pentiumIII an Hp e-pc model of cpu.
all is working except when i connect to the internet it restarts.
i suspect there is a virus.
so i scan with it with avg and found a virus at first then i try to remove it.
then i scan again with avg and found no virus.
but still it restarts.
