reinstall

Do you have acces to your database via phpMyadmin? If so, go in there and select all the tables that have wp- prefix and “drop” them.
If you cannot do that – just edit your wp-config file and change the table prefix from wp_ to wp2_

Unless you learn to give full sentence descriptions of what you did (step by step) and what error you encountered – nobody is going to guess your problems.
More info Using_the_Support_Forums and http://wordpress.org/support/topic/39501