Which PC power supply to buy

Hi how's everyone, long time no see. I have been very busy with work and family lately. I am trying to fix a friends computer, i have re-installed xp on his pc and everything runs smooth, but there still is an issue of noisy hardware. Apparently the power supply he just replaced last month is the culprit. It is a PoweMax KY-550ATX model and it specifiy's it's 450 Max watts and damn it makes so much noise. I am not sure if it's suppose to be this noisy or if it is failing/dying. So now i am on a hunt for a new power supply for my friend's pc. I didn't know much about power supplies before this, i have read tonz of articles and basic guides and now i know quite few important things, but i wanted to make sure with you geniuses as to what i have gathered from my reading is accurate. So let's get started i wanted to know is this that

1) how to find out which power supply to get 20 pin or 24 pin ? I took out my friends previous power supply and counted the connecting pin which goes into the motherboard it counts 20 pins, so this is how you know how many pins you need right ? But i also see another small connector which has 4 pins which also goes into the motherboard, so if we count these pins as well this makes it a 24 pin connector right ? I am confused can someone explain to me.

2) according to the type of answer for the above question, can you recommend any good brands of pc power supply or even better can you please specify a pc power supply from http://www.tigerdirect.ca/applications/ ... ?CatId=106
just keep in mind that my friend is an avergae user not a hardcore gamer, he's just a regular windows applications user

Thx in advance

Those extra 4 pins are for another connector or some newer motherboards and don't count as the 24, if you only counted 20 then thats all you need as all new power supply's come with the extra 4 plug.

If you buy a power supply with the 24 plug usually the extra 4 you don't need can be unclipped so thats not usually a problem.

Have a look at some of these:
http://www.newegg.com/Product/ProductLi ... ly&Ntk=all

Ok thx for your reply "tomrulez" i will go to a computer shop soon to find the 20 pin power supply. Thx for your help

Its alright, glad I can help.