Guild Wars lag problem

[savlon karaii]

I've just started playing Guild Wars and I'm loving it, except that it's constantly laggy whenever I play.

My computer stats are:

Acer
Celeron(R) CPI 2.66GHz
1.18 of Ram

I close down all running programs when I start the game, but for some reason, the CPU usage is constantly on 100%.

Any help would be appreciated!