Also I doubt it's a faulty PSU those things are resilient, a CPU will die long before PSU does.
Actually, that's not the case at all. CPU failure rates are VERY VERY LOW. Unless you're overclocking wrongly and pumping too much voltage through it for an extended period of time, they just don't die (even then, they tend to degrade, rather than die outright - you can turn a motherboard on without a CPU, it will just beep and fail to POST)
PSUs on the other hand, especially consider the number of low-quality/budget models, fail fairly often. In my experience (during 3 years as a PC repair tech), PSUs are a high-failure-rate item (as are HDDs, memory) and I have seen ONE bad CPU, which was on a system in a highly polluted-air environment, where the air was slowly corroding components - so it's not even a normal failure. To clarify further, that CPU did not die outright, it just wasn't stable at stock speed (200MHz under was fine).
If it won't turn on AT ALL (no noise, no fans, no lights), then it's probably 85% likely to be the PSU and 15% the motherboard. There are... questionably-safe ways of testing if the PSU will turn on by hotwiring two specific pins on the 24-pin plug, but the safest way (for you, not the parts) is to borrow or buy a new PSU and try it. Even if the mobo is dead, the PSU fan should kick in, so it's almost certainly the PSU.
Of course, in the event that the PSU blew catastrophically, it could have taken out other components. Not that common, but keep it in mind during troubleshooting. Good luck!