Did you try to search like this:
site:yourdomain.com
If no results are found that means your website is deindexed. If some results appear that means you got penalty.
Blog Commenting can give you positive results if you comment on low OBL, high PR, do follow blogs. These are hard to find and sometimes even harder to leave your link so I would recommend to use services for this but they cost a lot more than just spam comments.