Erudite theme

http://www.w3schools.com/css/css_link.asp
http://www.w3schools.com/Css/pr_text_text-decoration.asp

link to your site?

(it is easier to help with formatting issues when viewing the site.
there are too many themes out there to be familiar with all of them)

in erudite.css:

/* Main Links */
.entry-content a {text-decoration:none; border-bottom:1px solid #aaa;}
.entry-content a:visited {border-color:#ddd;}
.entry-content a:hover {border-color:#555; text-decoration:none;}
.entry-content a:active {color:#55f;}

try and change to:

/* Main Links */
.entry-content a {text-decoration:none; }
.entry-content a:visited { }
.entry-content a:hover { text-decoration: underline;}
.entry-content a:active {color:#55f;}