The exact heuristics behind question bans are not known outside of SE. Looking at your profile, you have 3 deleted questions, 4 closed questions and sundry downvotes which is somewhat more negative then you state above.

If you are getting the message:

> Sorry, we are no longer accepting questions/answers from this account

Then [you need to see this question][1] for detailed information on why you're banned and what you can do about it.

In short:

- There is an automatic filter that will ban questions and/or answers from IP addresses or accounts with a history of extremely poor posts.

- The details of the filter are secret, but it is partly based on downvotes.  If your questions and/or answers are getting many downvotes, you are likely to be banned.

- Deleted questions and deleted answers count towards the automatic ban.  If a large percentage of your posts are deleted by yourself or the community, then apparently they were not suitable for the site.

- In order to get un-banned, you need to edit some of your existing questions and/or answers to improve them.

  [1]: http://meta.stackexchange.com/questions/86997/what-can-i-do-when-getting-sorry-we-are-no-longer-accepting-questions-answers