#On ubuntu
sudo apt-get install ncbi-blast+
#Ubuntu Conda installation
conda install -c bioconda blast
#Windows installation
First:
Download ftp://ftp.ncbi.nlm.nih.gov/blast/executables/blast+/2.7.1/ncbi-blast-2.7.1+-win64.exe with your web browser.
#If that FTP links does not work, try HTTP instead http://ftp.ncbi.nlm.nih.gov/blast/executables/blast+/2.7.1/ncbi-blast-2.7.1+-win64.exe
#Run this
installer using the defaults, it should put BLAST under C:\Program Files\NCBI\blast-2.7.1+