I need a help to this problem , I have these things :
1) ATX power supply with +5v GND GND +12V
2) a transformer from 220 to 110 and a bridge to get +110V and GND

but when I connect the two grounds of ATX power supply to GND of bridge (after a transformer) then the circuit breaker is down. and disconnect all connections to these terminals but the porblem is the same I don't know where is the probelm.
I measure from GND of ATX to positive terminal of bridge it gives me +50 but with the GND of bridge it gives me -50V ???????///

I need help ?