I am using Wamp server, I reinstalled Wamp after uninstalling it to try Xaamp.I have completely removed all of the Xaamp files.Recently,I opened my phpmyadmin directory and discovered an error message which hinted to me that there were two MY SQL servers installed on my computer(please refer to http://i89.servimg.com/u/f89/13/69/31/58/sql_mi10.jpg ). I was using an older version of the MY SQL server before I uninstalled it. I am now using a later version. What could be the cause of this error?

The notice shows two warnings, and not errors as such. One, that your PHP Mysql library version is an older version than that used by MySQL server.

For this I suggest that you copy the libmysql.dll file in the MySQL bin directory into the PHP directory. The bin directory of MySQL will always have the most up-to-date version of libmysql.dll.

Two, the second warning (which is the about the root password) says that you haven't set a password for the root account of MySQL and it is a security hole which can make intrusions easy. And it really is that way. So change the default settings in your my.ini/my.cnf file to have a password set for root account.

I don't understand... You're using Xampp together with MYSQL?

Huh! Are you talking to yourself ?
Where has verruckt24 mentioned about Xampp ?