Blog and entire domain disappeared

Hi I’m using WP on my hosted domain (http://www.fleamall.com/blog) and my entire domain including blog and other pages disappear after successful post or comment from only two allowed contributors. It will post fine, but then when you go to preview your page everything freezes and from that point NOBODY on the same IP or network cannot view either blog or root domain (http://www.fleamall.com)
I can ping the domain successfully from command prompt, but I just do get Internet Explorer cannot display the webpage
This problem can be caused by a variety of issues, including:
•Internet connectivity has been lost.
•The website is temporarily unavailable.
•The Domain Name Server (DNS) is not reachable.
•The Domain Name Server (DNS) does not have a listing for the website’s domain.
•If this is an HTTPS (secure) address, click Tools, click Internet Options, click Advanced, and check to be sure the SSL and TLS protocols are enabled under the security section.

If I go to a different computer (IP) I can view the page just fine. I haven’t tried post a topic from other IP yet. I’m using only Aksimet and Counterize II plugins and that is all. Page is hosted with 1and1 and was fine until I installed WP. This happened many times and sometimes page becomes inaccessible for week or more!!!

I cannot even login through FTP to upload new version or disable plugins I do get connection failed: connection lost.

Thank you for all your input