Hi Ismath,
If you do a search of the forums, a bunch of suggestions come up - I've used these suggestions in the past to create the following css for my own site. I'm sharing the relevant bits in case it's helpful for your situation:
/* Hide Link on User Preferences Page */
#page-user-preferences a[href*='language.php'],
#page-user-preferences a[href*='forum.php'],
#page-user-preferences a[href*='editor.php'],
#page-user-preferences a[href*='course.php'] {
display: none;
}
/* Hide Link on User Preferences Page */
#page-user-profile a[href*='
blog/index.php'],
#page-user-profile a[href*='notes/index.php'],
#page-user-profile a[href*='forum/user.php'],
#page-user-profile a[href*='blog/index.php'],
#page-user-profile a[href*='plans.php'] {
display: none;
}