The connection to adb is down, and a severe error has occured.

1.报错：
The connection to adb is down, and a severe error has occured.
这个问题谁能解决啊
解决：
cmd跳到sdk tools文件路径下
adb kill-server
然后再adb start-server

2.报错：
The connection to adb is down, and a severe error has occured.
[2010-03-11 09:36:56 - HelloOPone] You must restart adb and Eclipse.
[2010-03-11 09:36:56 - HelloOPone] Please ensure that adb is correctly located at 'D:\OPhoneSDK_1.5
\platform-tools\adb.exe' and can be executed.
解决：
方法1.cmd中adb kill-server，然后adb -startserver
方法2.方法1不管用，那么在任务管理器中杀死adb.exe，然后重启Eclipse。
方法3.方法1和2都不管用，那么查看最后一句报错中：platform-tools中是否有adb.exe（我的错误就是在相关路径下面没有platform-tools文件夹
，所以我选择新建一个文件夹，并且把tools中的文件全部复制到platform-tools中）
3.前面的方法试了还是不行的话，建议重新装一个系统，最好换个系统。有些大牛也说过：MS存在一些小问题[size=large][/size]

附
启动和关掉 adb服务器 
当你启动 Android服务器时，adb服务器也就会一起启动。当你无法确定 adb服务器是否已启动？可以用“adb start-server”命令来启动 adb服务器，
如果已启动就不做任何事，尚未启动就会直接启动 adb服务器。若你不想继续进行调试监控，则可以用“ adb kill-server”命令来关掉 adb服务器。 
E:\Android\android-sdk-windows\platform-tools>adb start-server
E:\Android\android-sdk-windows\platform-tools>adb kill-server
E:\Android\android-sdk-windows\platform-tools>adb devices
* daemon not running. starting it now on port 5037 *
could not read ok from ADB Server, error = 109
* failed to start daemon *
error: cannot connect to daemon
E:\Android\android-sdk-windows\platform-tools>adb devices
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
List of devices attached
2CBE000400000001        device
 
android adb shell:unknown host service
我们在Windows DOS窗口中输入adb shell后，会出现如下错误： adb server is out of date.  killing... ADB server
 didn't ACK * failed to start daemon * error: unknown host service   ，出现这问题是因为你的电脑上安装了豌豆夹造成的，只需打开“任务管理器”，找到
'wandoujia_helper.exe'，把这个进行终止掉就可以，