I have my own domain name online, but my email account is setup through a separate company (even though it has the same dot-com name). The problem is that my email has spontaneously stopped working without warning. As hard as I try, I can’t even find who provides that email account. When I go to pop.mydomainname.com it won’t recognize my login’s. Is there any way to identify who out there controls my account and yet I can’t move the account to another company (which I’d love to do)?
Dale, if worst comes to worst all you have to do is contact the ISP who is doing your DNS hosting and tell them to change your MX record to match your new POP provider.
Possibly the simplest way for someone such as yourself to get this done would be to
A) contact a firm you’d like to have host your POP account now and in the future
B) explain the situation to them.
They will likely be willing to dig through the crap associated with this situation and get your web services set up as you like them. They will of course need for you to give them your permission to make changes with whomever controls your DNS registration.
Use the utility on this page to find your MX record. (it doesn’t have a “submit” button on the form, so make sure you’re using IE and hit ‘enter’ after putting in your domain.)
It’s not the best site, but it does the job (there are others if you Google “MX lookup”).
After you’ve entered your domain, check out where the page says “ANSWERS” and below that will be the MX record for your domain. Mine looks like this:
That means that the mail for mysite.com is being handled by mail.mysite.com.
After that is a list of nameservers, too, that are responsible for telling all of the Internet where your site is located, including the main IP addresses for the mails erver and nameservers.
Most likely you have POP access for the domain you own and whoever is hosting that domain needs to change the MX record for you. You probably have also lost some email in the meantime 
You can try http://www.betterwhois.com/
Input the where name in the box. In other words, the right side part of the email address.
you@thisplace.com (thisplace.com) to find out who owns it.