I can't recall hearing of anyone producing lower quality motherboards than PC Chips!
As far as I understand, the only parts that have changed since it died are the case (which shouldn't matter unless it shorts something out or causing unusually yucky stresses, both of which are unlikely), the powersupply, and the disk. Consider just how much PCChips mobos suck, I'd say it is quite likely it is the one that failed (they don't even tend to work particularly well when first installed even). Still, here are things to try:
I very much doubt the PSU isn't powerful enough - 430W is probably AT LEAST twice what you need and should also have enough power on the different rails. I haven't researched Thermaltake at all so I've no idea who makes them or if they're good. That said, some PSUs refuse to start if the load is too low but I don't think that is what is happening here.
1)Remove everything but the motherboard, the CPU, the memory, the front panel connectors and the graphics card and try turning it on. If it works at this point, the fault is either with the motherboard or one of the parts you've removed. Try reconnecting them one at a time (and this is where I add that the power cord should be out whenever you remove or install non-hot swap hardware so that I won't have to risk getting sued ). When the system fails to turn on again, you've probably found the faulty part. Try it on another computer - if it works there, it probably is the motherboard.
2)Next remove the graphics card. If it appears to start (i.e., fans spinning) and you get beeps from the speaker, the graphics card (or possibly) the motherboard is bad. Test the card in another computer.
3)Remove the memory as well. Same as above, check if it starts, and then beeps. If it does, you either have bad memory or a bad motherboard.
Unless you've removed the heat sink/fan assembly at some point, it is unlikely that the CPU is bad.
Just to annoy people, different companies have different beep codes for various faults. It should say in the motherboards manual which beeps correspond to which failure.
You didn't mention what the old parts where, does the old motherboard work with the same CPU? What model is it?