I am buying my pc.

Ok ive been wanting to upgrade from my current pc, its pretty old, medium ram and low disk space. Its windows xp one of the first one.

I was looking into buying a new one and a i found a great company in uk selling custom made pcs.

I was looking at one with 1.2gb/2gb ram and it was i think 200+gb hard disk. And a good graphics card. 17 or 19 flat screen mouse and keyboard. I don’t understand much about the processor and its speed. What would be a good processor and what is a good (1.80GHz, 800MHz, 2MB) size not familiar with the numbers. I will need a pretty fast pc for design and running a lot of software.