What is the Average Life of a PC?

I want to know for instance what would be the Average Life of a PC.

it depends if you do overclock, if your components toast ... and so on..

For my part, I have never slammed a PC. It must be said that I do not overclock also. I usually change it when things do not work, or when the machine is not pretty fast (which my case now). I am not a big gamer also. I played a few games, but not the most demanding and not in the largest resolution. So as said above, it depends on your usage and maintenance of your pc (and a little luck also at times). However, I would say an average life of pc would last for 4 year.

It depends on many factors obviously, including how much of a power user you are and if there's a toddler around to shove things into various orifices and break off the CD/DVD tray. In a corporate environment we usually assume 3-4 years, which is why I prefer to get systems on 3 year leases with 3 year warranties.

I would say it depends on the price you pay. Is it custom or brand name?
I build my own computers. When I spent over $5000 on my computer it lasted for about five years playing all games at max settings. It is now a fileshare server in my house. It still works fine, but it can't compete with newer computers.
I just built two more computers for my wife and I. They are already having a little trouble with newer games with an Nvidia 8800GTS, 2GB of higher performance RAM, 150gb Raptor Raid 1, and a dual core intel. I just need to get a second video card and it should be good.

I think it just depends on what you get. You can't just buy any computer and expect it to last as long as the computer that cost $100 more. They will have different components.
Usually though, a computer should last at least 3-4 years for basic tasks.