We all hope it is only the power supply at fault here...(many brand name 550-600 watt units for $50-$55 available)
(NOTE: if you or a friend change the PSU (many of which are modular with special cables), be sure to change ALL PSU associated cables with it, do NOT reuse old power cables to GPU, drives, or 24 pin ATX to mainboard, etc..; failure to heed this can/will burn out drives quite as quickly as with initial power on)