I'm going to replace my CPU chip with atleast a 2.6 ghz athlon. Would I need to upgrade my power box(250 watt) to have it installed and work properly? Also, I'm not sure what my motherboard is but its about 2-3 years old, what is the minimum-recommended required motherboard to have it installed and work properly? Why should poor computers exist?

You can't replace an Intel Celeron with an AMD CPU.

If you replace your CPU with a AMD you need to upgrade your motherboard as well. You might also think about replacing your RAM to match or better the bus speed of your new CPU. AMD is a good choice though you get more power for the $ and they are still faster than any intel per PCworld benchtests. As far as the power supply goes you could probably get away with the 250 watt. Keep in mind though the more power hungry toys you put in the pc the more power it will need. If you have more than one of any of these items you should upgrade your powersupply: High end Video card Optical Drive Hard drive I would start shopping at www.newegg.com they are very reputable and the prices are good. They also have an excellent search tool that will really help out any beginner. Good luck.