If you're able to edit the html, you can add a span around the checkbox, and style that instead of styling the checkbox directly.

<style>
  label {
    float: left;
    margin: 5px 0px;
    width: 150px;
  }
  label + * {
    margin: 5px 0px;
    width: 200px;
  }
  .clear {
    clear: both;
  }
</style>

<div>
  <label for="autologin2">Remember Me 2</label>
  <span><input type="checkbox" class="checkbox" id="autologin2" name="autologin2" value="1"></span>
  <div class="clear">
</div>

jsfiddle