Digital BW, The Print

I have spent the day playing with lots of photoshop colour settings etc 
mainly in response to Clayton's articles on using dot gain profiles 
etc. All seemed well when I turned off but next time I fired up 
photoshop there is a strong warm cast. The only setting which will 
banish it is to turn off the colour management altogether. Windows is 
operating at the correct colour.
Just found another way to correct the colour. It is correct if I click 
View/Proof set up/Monitor RGB. The default has always been Working CMYK 
up to now with no problems.
This is driving me mad. Help would be greatly appreciated.
Pete.