what is the dew point inside a pc if the processor is 35c system temp
is 40c and graphis cards at 60c.the machine is water cooled and im
going to add a chiller. what i want to know is how far can i cool this
without dew forming?i can add case fans if needed and i live in
scotland(normaly cool)if the case temp is 18c when will dew form if i
pump 5-10c of cold water round my cooling tubes? can i go more or is
this to much?

It depends on the enviroment, but im 99.99999999999999999% sure that
you can cool some more, unless it is blistering hot, you will be fine.