Is there any website for finding SEO problems of a site?
First of all, I would recommend check the website for the items mention in following two articles:
- 10 Common SEO Mistakes that can Destroy Your Website [Part I]
- 10 Common SEO Mistakes that can Destroy Your Website [Part II]
MakeUseOf also profiled a number of really good online SEO check tools in its Directory. See http://www.makeuseof.com/dir/tag/seo/
Oh, there are dime a dozen. They are commonly called as SEO Tools and if you Google for them, you will get many of them. But don't rely on them totally as some reports can be misleading. Some will even return an erroneous "site not found" message. As SEO is about various facets of a website, I am not giving you a list here. Just type something like Online SEO Tools in Google and you will get a lot to trawl through.