Hiding the quick launch in SharePoint can be done in a number of different ways but the easiest way is by overriding the current css class implemented by "Quick Launch" in Content Editor WebPart (CEWP) :
Paste the following code in a CEWP and it will hide the quick launch bar :
SP2010
#s4-leftpanel{
display:none
}
.s4-ca{
margin-left:0px
}
SP2013
Paste the following code in a CEWP and it will hide the quick launch bar :
SP2010
#s4-leftpanel{
display:none
}
.s4-ca{
margin-left:0px
}
SP2013
.ms-core-navigation { DISPLAY: none }
#contentBox { margin-left: 0px }



