Navigate from the Dashboard to Layout > Page Elements.
Click on Add a Gadget in the sidebar or other location if you wish
Select a HTML/JavaScript gadget from the list of gadgets
Paste the following code into the content box of the widget:
<form><select name="menu" onchange="window.open(this.options[this.selectedIndex].value,'_blank')"
size=1 name=menu>
<option>- Your Menu Title -</option>
<!-- Change the following links to your own -->
<option value="http://URL of link1">Link 1</option>
<option value="http://URL of link2">Link 2</option>
<option value="http://URL of link3">Link 3</option>
<option value="http://URL of link4">Link 4</option>
<option value="http://URL of link5">Link 5</option>
<option value="http://ncbloghelp.blogspot.com">Blog Help and Tips</option>
</select></form>
Replace _blank as follows:
To have a new window open leave the same
To have the new page appear in the same window replace _self
Replace - Your Menu Title - with a title of your own
For each instance of the option values highlighted in red substitute your own links and link names. For example:
<option value="http://NCBLOGHELP.blogspot.com">Blog help and tips</option>
Click Save
Use drag and drop to position the drop down menu widget in the location you want it within your sidebar and save any changes
Click View Blog to admire the new drop down menu in the sidebar of your blog