How To Shrink LOG FILES

I have a SQL SERVER 2005 Data Base:

Recently I tried to delete some data from this DB, Because  the DB collect event from special devices and some event were too old ,so no need to stay in my DB. The delete action failed (SQL Server : no enough space in disk to do that ) and after this failure the log file size(150 GB) became double of data file (80 GB).

I did Backup several times , but the size of log file never decrease.

I did shrink action and no  deceasing.

So please how to shrink log file (before delete action the size was about  1 GB).