To prevent others with a nasty intent from accessing your WP-Admin page on your WordPress site use the following code on your wp-admin/.htaccess file using the static IP address from approved computers.

In the vase below I am only allowing access from my desktop and laptop

AuthUserFile /dev/null
AuthGroupFile /dev/null
AuthName "WP Access Control"
AuthType Basic
order allow, deny
deny from all
# George Ross MacPro
allow from xx.xx.xx.xx
# George Ross MacBookPro
allow from xx.xx.xx.xx

If you need to access your WordPress site from other computer simple add another 'allow from xx.xx.xx.xx' line.