Please perform every step in the READ before posting about boot/no video problems! sticky at the top of the forum. It was created to troubleshoot this exact type of problem. It's likely something's either shorted out or you forgot to plug something in since it quit working when you moved it from one case to another.
Try to borrow a known good PSU. Or better yet, see if you can test your PSU in another working system. If you cannot do that, try to borrow a DMM to measure the voltages. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on.
The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.
This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.
sorry took so long to reply, real busy this time of year at work. psu is fine i just rebuilt another system using that psu and its running fine. now the problem i have is that is it the cpu or the mobo and how to tell.