System is shuting down

Hello,
I am having a problem, like my pc is not working, its not getting started, yesterday i am doing some work, at that time screen showed me System is shutting down, after that i tried many times to start my pc but it was not done, i tried all the things, like i changed my Ram and started but no use, i removed and attached all the vire links and started but no use, just its starting and showing welcome screen and agian its going to shut down, immediatly i callied to hardware person he told me that, Sir in your system Smps problem occured and u need to change that SMPS, but i am not in a situation to pay what ever the amount he was asking, now i don't have money to pay him, so i am requesting you to is there is any solution where i can get my work done. and is it really SMPS proble, if yes tell me plz what would be the new SMPS Price in the market.. its urgent plz revert me immediatly.