Never allow anyone to login to your account ever. I have used this theme and if I had $10 for every time someone has said it does'nt work when it does I would be rich.
Theme description: http://theme.wordpress.com/themes/sight/
This is the live demo that applies to us at WordPress.com http://sightdemo.wordpress.com/
This theme has a featured post slider and that's what you see on the demo site ie. on the demo site but I do not see it on your blog.
Sight displays up to 30 of your latest sticky posts that have featured images in a prominent slider on the front page. To add a post to the slider, mark it as sticky http://en.support.wordpress.com/posts/post-visibility/#sticky-posts and give it a featured image.
Sight featured images
Large: 640 x 290 in the Sticky posts slider
Small: 290 x 290 thumbnails are used on the home, category, tag, archives, and search pages.
Setting a Featured Image http://en.support.wordpress.com/featured-images/#setting-a-featured-image
If you don’t see the Featured Image module on your Add New or Edit Post page, please make sure you’ve selected Featured Image in your Screen Options. http://en.support.wordpress.com/screen-options