Depends what you mean by explosion and also what PSU you have (i am going to assume a small pop not violent explosion). Some PSUs have been designed to protect the computer in case some of the components "explode". If the PSU is from a pre-built computer, chances are these PSUs dont have very good protection for your computer.
So i assume your PSU has stopped working, you should send your computer into a repair shop and tell them test the PC. They will tell you if the parts in the computer no longer work, most places can do this right in front of you and they will be happy to do so if you don't trust them.