I got myself an S-video to scart lead, plugged it into the appropriate places and turned on my laptop (Centrino, Samsung, about 4 months old. Windows XP Pro) i turned on the TV and it was in black and white! i went through all the options on the computer, tried all the PAL settings (im in UK) and they were all black and white.
I have tried it with another TV and... still the same, so i have ruled out TV fault
Any thoughts or if you want more info, just ask