STEPS TO DELETE LOG FILE OF A DATABASE..
1.Backup the database
2.Detach the database, either by using Enterprise Manager or by executing : *Sp_DetachDB [DBName]*
3.Delete the transaction log file. (or rename the file, just in case)
4.Re-attach the database again using: *Sp_AttachDB [DBName]*
5.When the database is attached, a new transaction log file is created.