Messed up sidebar position

I have somehow managed to mess up the location of the sidebar on my site http://.manukhanna.com/blog:

1. on the homepage, the sidebar displays below the page
2. on page 2 (about), it is displaying fine
3. On page 3 and 4, sidebar does display in its position but the About box has vanished from it.

I have made a lot of changes to the theme so cant’t just dump it and go in for another one, will loose everything.

much appreciate.