how stupid are canon, adobe and windows!!!!
Well, you can't blame Canon for being stupid, they provide editing software with the camera, if you want to choose something different then get something compatible with your system. Same goes for Windows, do you expect them to never upgrade the OS in case some software producer doesn't make their software compatible with out of date versions?
OK, Adobe, maybe you have a point as there are still a lot of XP users out there, but you are going to need a fairly up to date computer to deal with 5DIII raw files, I would have thought that anything going back to XP days would have to be fairly well upgraded to have any sort of speed. Of course, XP has a fanbase and can still be purchased, but it is a little over 6 years now since Vista took over. I guess Adobe are just assuming that people using LR4 are going to have something built since then to run it on, as it does take a lot of processing power with high mp files. Of course, if you put XP on a newish machine from choice, this is one of the pitfalls of the decision to use an "out of date" OS, in the eyes of the software producers. When using old software you need to check the system requirements before buying.
In the computer business, the world keeps moving on and older software needs to be replaced. Yes, it is a bummer. I have a load of favourite games that I cannot play because they don't run on the newer windows versions. That is the price of progress unfortunately.