When you installed mysql first time all goes well but if due to some reason you need to uninstall then install mysql agian follwoing problem always occure at configuring it
Processing configuration…
/ Prepare configuration
/ Write configuration file (c:\Program … \my.ini)
/ Start service
x Apply Security settings
the last step (Apply security setting) always get fail. I also had the same problem and it took so much time to me to solve the issue. on the internet you found lots of solution
related to properly uninstalling mysql like
-Unintsall by Add/Remove program(In windows XP)
- delete Mysql folder in program Files(c:progme Files etc) directory
-remove entry from registry(regedit)
- remove entry from system configration (msconfig)
- check by (Alt+ctr+del), that my sql service is runnign uder proccess, if it is then stop it.
- better to restar your system(optional)
- Now reisntall and configure it agian.
If this solution works then its greate, otherwise i have another solution for your problem
for the 2nd solution you have to dlelete some enrty from mysql tables to congfiure mysql easily.
so follow it as following
1 -stop if mysql service running(offcourse its running after installation), use (Alt+ctr+del) to stop form procsess
or use it http://dev.mysql.com/doc/refman/5.1/en/windows-start-service.html
2 -Open command promt (in windows Menu>Start>Run>CMD )
“C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqld.exe” –skip-grant-tables
3 – Let this window open , open another command promt
Menu>Start>Run>CMD
“C:\Program Files\MySQL\MySQL Server 5.1\bin\mysql.exe” -u root
4 -Set new password for root user (or your user that given it another name)
You’re now connect to MySQL, you have to modified the root account in the date of MySQL
mysql> use mysql;
mysql> UPDATE user SET password=PASSWORD(‘motdepasse’) WHERE user=”root”;
mysql> flush privileges;
mysql> exit;
5- Restart with MySQL Commant Line Client (mean restart the mysql service).
Thats all you have to do!!!
Leave your comments, if this solution works for you (offcourse it will work, as it work in my case) 
