I have moisture between the glass on my kitchen window. The double glazed unit needs to be replaced.This involves removing the glazing rubber from the inside of the window before I can go outside to adjust the glass inwards to allow the glazing beads to be taken out. This system stops someone just taking the glass out of your window to break into your house. It's a little difficult but if you take a little time and are not too heavy handed it is possible to do it yourself.
Hope you find this useful.
Cheers
Gerry