PC won?t turn on…at all

Here is the problem, I have a 300w PS powering a PC…Celeron 2.40GHz, 512MB RAM, DVD, CD ROM, CD-R/RW, 3 Chassis Fans, HDD Fan(mounted onto the HDD,underneath) and a Tt 4 Fan control 5 1/4? deck.
About 3 hours ago, it just turned off and won?t turn back on. I noticed that the Volts on the PS were moved to 230v not 115v which it was supposed to be on. I tried changing the PS to a 350w PowerMax the PC just turned on for 3 seconds. I assume that I need a 400w to 500w PS. Is there any chance that I damaged the motherboard? It is a SOYO PVM…Prescott Ready. Or damage the Processor? Why won?t it turn back on?