Do you understand about static electricity and electronic components? No not really just a little bit...Why?
Static electricity can discharge from you to parts of your computer and destroy it so you must take steps to prevent this.
Static electricity is that spark that you get when you drag your socks along a carpet and then touch a metallic object. The amount of damage that shock can cause to every single component on a PC can often be terminal. Surprisingly enough, you don't even need to feel that spark to have damaged an electronic component, as the amount of current required can be so small as to be virtually imperceptible.
That is why, no one at no time should ever open up a computer case until they have secured themselves to a static electricity grounding solution. One of the best and cheapest is that little wrist strap.
Here is a little reading for you. Ignore the bit in this article about checking you AC mains. > http://www.pcworld.c...to_your_pc.html
Handling components, > http://www.pcguide.c...entHandling.htm
Always unplug from the wall socket, Take anti static measures and NEVER poke inside the PSU EVEN when it is unplugged. The PSU can hold enough voltage inside for a couple of days, (a bit like a large battery) and the high amps can burn you or could even be fatal.
Please post back that you do understand.