i don't remmember if there was some smell...the pc is turning on and off right away..and the psu is eight years old..So, is your PSU dead/fried ? How do you exactly know that it has indeed died ?? Any symptoms on your PC ? Your computer turned off, or there was some burning smell, and/or you are enable to boot your PC ?? How OLD is this PSU ?
List your other PC specs first. Which GPU were you using with this power supply ? You need to replace/chnage your current PSU, assuming it is dead.