Java – Hadoop does not start any data nodes on Windows 7

I built Hadoop on win7-x64. I configured hadoop and when I run Hadoop, it fails to start the data nodes. It displays the following error. It shuts down the data node. How do I fix this error? Thank you.

14/08/01 07:36:23 FATAL datanode. DataNode: Initialization failed for block pool
Block pool <registering> (Datanode Uuid unassigned) service to localhost/127.0.0
.1:9000
java.io.IOException: Incompatible clusterIDs in C:\hadoop\data\dfs\datanode: nam
enode clusterID = CID-72be3471-e6d9-4c1a-9d2c-d66938de8c93; datanode clusterID =
 CID-0000641d-13c0-41cd-ad5b-fd5854906ad0
        at org.apache.hadoop.hdfs.server.datanode.DataStorage.doTransition(DataS
torage.java:472)
        at org.apache.hadoop.hdfs.server.datanode.DataStorage.recoverTransitionR
ead(DataStorage.java:225)
        at org.apache.hadoop.hdfs.server.datanode.DataStorage.recoverTransitionR
ead(DataStorage.java:249)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.initStorage(DataNode.
java:929)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.initBlockPool(DataNod
e.java:900)
        at org.apache.hadoop.hdfs.server.datanode.BPOfferService.verifyAndSetNam
espaceInfo(BPOfferService.java:274)
        at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.connectToNNAndH
andshake(BPServiceActor.java:220)
        at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.run(BPServiceAc
tor.java:815)
        at java.lang.Thread.run(Thread.java:662)

I solved this problem,
Simply remove the dfs.namenode.name.dir and dfs.datanode.data.dir properties in hdfs-site.xml