While most of us have moved on to modern versions of Windows such as Windows 7, 8, or 10, there may be a few folk still running XP and Vista. If anyone is still running these older versions it might be time to change if you want support from Blizzard. Surely nobody is running these still?
A post from Blizzard announces the discontinuation of support for XP and Vista later this year.
After these older operating systems are no longer supported, the games will not run on them, so we encourage any players who are still using one of the older OSes to upgrade to a newer version. We’ll be rolling out this change on a staggered schedule, and will post further notices as we get closer to making the change for each game.