From which version of DNN did you upgrade to 4.4.1? Were there any error messages that occurred during the process?
Just in case you missed it, I will assume that you replaced your existing web.config file with the version that came with 4.4.1. You should also have copied some data out of your old web.config an added it to the new web.config.
If you didn't do this, or even if you did, I'd recommend that you view the
How to Upgrade DotNetNuke v3.x to v4.4.1 tutorial. Even if you are upgrading from a version 4.x system, most of the concepts are there.
I would also recommend Mitchel Sellers' blog at
http://www.mitchelsellers.com/Home/...ault.aspx. He has some fairly detailed instructions.
I also hope that you have a good backup of your web directory and database so that you can restore to the previous version if that is necessary.