I just installed CS2 and half of my filters are showing up as faded out and I can't use them.
#1
What kinds of files? 16 bit? CMYK?
#2
Many filters only work if the image is in 8bit, rather than 16 bit. You can make the necessary change using Image > Mode and from the drop-down menu choose 16 bit
#3
Bernard meant choose 8 bit.
Also, many filters won't work on files in formats other than RGB. If you can't use a given filter, the file may be palletted (e.g., GIF), CMYK, duotone, etc. You would have to change the Image Mode to RGB/8 to use all filters.
#4