Adb as working fine for me right up until today. Now, when I try to run adb kill-server, adb just hangs. If I set ADB_TRACE to 1, I get
C:\Users\Jamie\AppData\Local\Android\android-sdk\platform-tools>adb devices
system/core/adb/adb.c::main():Handling commandline()
system/core/adb/adb_client.c::adb_query():adb_query: host:devices
system/core/adb/adb_client.c::_adb_connect():_adb_connect: host:version
Then it just sits there. I'm out of ideas!